Sport
Spin classes are hard exercise: the NHS (National Health Service) calls them very vigorous, and riders spend a third to a half of a class above the point where breathing gets hard, even when it feels manageable. A few months of classes improve fitness. The rare but serious risk is rhabdomyolysis, or rhabdo, a fast breakdown of thigh muscle, and most people it puts in hospital are healthy and at their first class.
This guide covers how hard a class is, a first class at your own pace, setting up the bike, rhabdo and its warning signs, knees, backs, necks, hands and saddles, heat, fluids and loud music, pregnancy and after birth, home bikes and children, and spin against running. It includes a first ride at your own pace and a strength workout for riders, with a 3D demo of every move.
The Compendium of Physical Activities gives a spin class 9.0 METs (metabolic equivalents), a measured value, and the NHS calls spinning classes very vigorous. In 20 active women, a third to a half of a class was above the ventilatory threshold, the point where breathing gets hard.
In 97 published cases after indoor cycling, most were healthy women at their first class; 7 developed kidney injury and none had lasting harm. One Singapore hospital admitted 93 people in 13 months, most at their first class, and 1 had kidney injury. Nobody has counted riders, so the risk per class is unknown.
The doctors who report these cases advise a gradual, low-intensity first session, and being fit didn't protect people. It's expert advice and our suggestion, never tested in a trial.
Sedentary women who went to gym classes about 2.6 times a week for 12 weeks raised their exercise capacity by 16% against controls. A review of 13 small studies found better aerobic fitness, blood pressure, blood fats and body composition, with diet needed for weight loss.
Spinning and Keiser set the saddle so your knee keeps a slight bend at the bottom of the stroke, about 25 to 35 degrees, with your kneecap over the pedal and the bars level with the saddle or higher.
Riding 90 minutes without drinking cost about 2% of body weight, and plain water worked as well as a sports drink. In 17 Boston classes, the music added up to about 9 times a full working day's recommended noise dose in one 45-minute class.
A stationary bike with a heavy flywheel, a resistance knob that also works as the brake when you push it down, an adjustable saddle and bars, and toe cages for trainers or clip-in pedals for cycling shoes. On many studio bikes the pedals keep turning with the flywheel, and EMD UK, the national governing body for group exercise, expects indoor cycling instructors to understand "free and fixed wheel".
Usually about 45 minutes: studied classes ran 35 to 50 minutes, and Boston classes averaged 48.9. Spinning's guidance gives seated flats at 80 to 110 rpm (pedal revolutions a minute) and hills at 60 to 80, with standing climbs, jumps between sitting and standing, sprints and loud music, often in a warm, humid room.
9.0 METs in the Compendium, a measured value. In 20 active women, average intensity looked moderate (74% and 66% of maximal oxygen uptake in 45- and 35-minute classes), but 52% and 35% of the time was above the ventilatory threshold, and oxygen uptake briefly went above the maximum measured on a treadmill in 10 of 40 sessions. Instructors in a standard 50-minute class worked from moderate-to-heavy to very heavy intensity, mostly very heavy; club members averaged 80.6% of heart rate reserve and rated the class 14.9 out of 20; and riding out of the saddle raised oxygen uptake without an all-out effort.
In a 90-minute class, men sweated about 1.1 litres an hour and women about 0.6. Without drinking, 90 minutes cost about 2% of body weight, and warmer, more humid rooms raised heart rate and perceived effort.
What the studies and our cycling page point to:
Cycling doesn't build bone, as our cycling page explains, so riders need strength and impact work alongside their classes.
Aerobic fitness, strong thighs and hips, a back, neck and shoulders that hold a riding position, and the restraint to ride at your own level, which matters most in a first class.
The rhabdomyolysis figures count hospital cases, not riders, so the risk per class is unknown. Other spin injuries have barely been studied; most of that advice is borrowed from cycling, and each note says so.
The numbers, by study:
Mostly healthy young women at a first class, who seek help 2 to 3 days later, but also unfit adults, a regular exerciser and a woman with sickle cell trait. One case followed only 15 minutes of a first class, another a 45-minute first session, and in one series cases followed a first session "regardless of the degree of previous physical training".
One cross-sectional survey of 457 adults aged 20 to 35 at sport centres, read as an abstract, linked spinning classes with knee injuries in women, and more frequent spinning with knee injury. No study has measured injury rates in spin classes. Our cycling page explains how saddle height changes the forces at the knee, and our knee pain, runner's knee, iliotibial (IT) band syndrome and knee arthritis guides cover the knee.
Source 31
There's no spin study. Spinning advises bars level with the saddle "or higher if you feel any discomfort in your back", and our cycling page covers numb hands and a stiff neck. Our back pain, neck pain and carpal tunnel syndrome guides cover these; we don't yet have a guide to the ulnar nerve at the wrist, often called cyclist's palsy, and our ulnar nerve entrapment guide covers the elbow.
Source 11
There's no spin study. Our cycling page covers saddle numbness, including the signs that need 999 (below). We don't yet have a guide to saddle sores.
In 17 Boston classes, riders spent an average of 31.6 minutes above 100 decibels. After spin classes, 25.9% of riders had ear symptoms, and 14.8% of people in fitness classes had ever had ringing in the ears afterwards. Temporary hearing loss showed in all 14 young adults who spent 60 minutes in a loud aerobics class, and in 41% of fitness instructors, and one man had sudden hearing loss after a cycling class. We don't yet have a guide to hearing and exercise.
In 19 children aged 18 months to 5 years, home exercise bikes caused hand injuries, and chains and sprockets caused crush injuries, including amputations. In US emergency data, children had about 1,551 stationary bike injuries a year, 56% of them not while riding, and stationary bikes were 26.5% of home exercise equipment injuries in children from 1990 to 2008.
One case report describes a clot in a leg vein that travelled to the lungs after a 25-year-old woman took up spinning. She had an inherited clotting tendency and took an oral contraceptive, and the authors single out hard standing cycling for people at high risk. It's a single case.
Source 40
No measure has been tested for preventing rhabdomyolysis or other spin injuries. The brands' and standards bodies' guidance is graded as guidance; the first-class advice is expert advice and our suggestion; each note says so.
As published, with their effect on injuries unmeasured:
EMD UK's indoor cycling scope of practice (5 June 2025) expects at least 3 months of attending classes before training, pre-exercise screening, supervision and adapting classes to each person, and an understanding of set-up, safety checks and fixed and free wheels, for healthy clients aged 15 to 65, or over 65 without long-term conditions. The Core Group Exercise Instructor standard of CIMSPA (the Chartered Institute for the Management of Sport and Physical Activity) names indoor cycling as a class type and covers verbal screening, putting off exercise when needed, and the talk test.
The case series' authors advise "a gradual start under adequate hydration and environmental conditions"; that "A graded exercise programme is advised at the first session"; "low-intensity training for all young women engaging in their first indoor cycling session"; guidelines and warnings; better education of gym owners, instructors and riders; and, with sickle cell trait, seeing a doctor before a first class. This is expert advice, never tested in a trial. Our suggestion: a beginners' or shorter class at your own pace, and 2 days before the next; our first spin class ride sets it out.
Cases followed a first session "regardless of the degree of previous physical training", and one was in a young person who exercised regularly. The risk is about how new and how hard the class is for you, so a fit runner new to spin starts easy too (our reading).
In 30 experienced riders, formulas for saddle height put only 20 to 33% of the women within the recommended range of knee bend, against 73% at their own preferred height; all the methods suited men moderately well. Our cycling page explains that a bike fit is for comfort and for when something hurts, with little injury data behind any knee angle. Our suggestion: ask for help at your first class, check the knee bend at the bottom of the stroke, photograph your settings, and change one thing at a time if something hurts.
Without drinking, 90 minutes of spinning raised heart rate by about 7 beats a minute, blood pressure by about 4 mmHg (millimetres of mercury) and body temperature by about 0.2°C, and plain water prevented it as well as a sports drink; in 14 men, drinking didn't change how much work they could do. Warmer, more humid rooms raised heart rate and perceived effort. The NHS advises more cold drinks when you're active in the heat, and our rhabdomyolysis guide says dehydration adds to the risk, but rhabdo happens without it.
Classes about 3 decibels quieter felt just as hard, riders often preferred the music quieter, and about a fifth of people in fitness classes found loud music stressful. The NHS advises ear protection around loud noise, and music only loud enough to hear comfortably. Our suggestion: foam or musicians' ear plugs, a bike away from the speakers, and asking for the music to be turned down.
The doctors who reported children's hand injuries found that supervision didn't reliably prevent them, and advise that children "not be allowed access to any stationary exercycle machinery, whether it is in use or not". Peloton says to keep children under 14 and pets away from its bikes at all times.
No measure has been tested for preventing rhabdomyolysis after a first class (our search). Nobody has studied clip-in pedals against toe cages, or the idea that saddle soreness goes after three rides. Perceived effort tracked heart rate poorly in one class but controlled intensity in experienced men in another, so use the talk test and how hard it feels, with heart rate as a check (our reading, as in our zone 2 guide).
From small trials and laboratory studies. How to fit classes into a week, and preparing for a sportive, are our suggestion.
In 42 sedentary women, 12 weeks of gym classes (about 2.6 a week) raised exercise capacity by 16% and lowered resting heart rate against controls, with no change in how the heart pumped or relaxed, and the carotid artery became more elastic. A review of 13 studies (372 people, 306 of them women) found that indoor cycling may improve aerobic fitness, blood pressure, blood fats and body composition, and recommended diet alongside it for weight loss and blood fats; there were few randomised trials. A 2026 review found a consistently high-intensity demand.
In 14 overweight young women with no control group, 36 sessions over 12 weeks lowered body weight by 3.2% and fat mass by 5%. Our weight loss guide explains that exercise on its own takes off about 2 to 3 kg on average, and eating less does most of it.
In 11 trials (724 people), stationary cycling eased knee osteoarthritis pain against no exercise, though the changes in stiffness and function were below what people notice. A spin class is much harder than the cycling in these trials (our reading), so start with easier rides; our knee arthritis guide explains more.
Source 51
Spinning's guidance: flats at 80 to 110 rpm and hills at 60 to 80, adding resistance or slowing down if you bounce. On a steep simulated climb, standing raised the knee's share of the work, and the authors advise standing "but not for long periods"; at very high power, standing lowered the knee's share. Our suggestion: build standing time gradually, and sit down when your knees complain.
Much of a class is above the ventilatory threshold, standing raises the effort, and heart rate lagged behind oxygen use at high effort in one study. Our HIIT (high-intensity interval training) guide says hard interval sessions once or twice a week suit most people, and our zone 2 guide that most other riding can be easy enough to talk in full sentences.
Cycling doesn't build bone, and strength training improved cycling power in trials, as our cycling page explains. Our strength workout for spin classes takes its doses from our workouts for cyclists.
No spin trial in runners was found. Our reading: spin adds aerobic work without impact, which suits injured runners and heavy weeks, but it doesn't replace running for running fitness or bone; our running page covers running training.
Our suggestion: 1 or 2 classes a week for the first 2 to 3 weeks, with a rest day after each, then up to 3 if you recover well. Not every class needs to be ridden hard.
Riders in one study used a 90-minute class to prepare for a 108 km road race. Our suggestion: spin builds fitness, but you also need longer outdoor rides for time in the saddle, bike handling and eating and drinking on the move; cut back in the final week and keep a few short efforts. Our cycling page covers road training.
Source 22
Expert advice from the doctors who report rhabdomyolysis after first classes, and our suggestion. None of it has been tested in a trial.
Book a beginners' or shorter class, arrive 10 to 15 minutes early for help with the set-up, eat something light and drink water. Trainers work in toe cages; clip-in cycling shoes are optional. Bring a towel and ear plugs. With sickle cell trait, see your GP first.
Ride at your own pace, whatever the instructor or the leaderboard says. Keep most of the class at a level where you can talk in short sentences, ride sprints easy or sit them out, sit down if your knees or back complain, and drink water.
Ease off for 3 to 5 minutes rather than stopping dead (our cool-down guide). Sore thighs for a day or two are normal; pain far worse than that, with dark pee, needs medical help the same day (below). Leave 2 days before your next class, and keep to 1 or 2 classes a week for the first 2 to 3 weeks.
Source 54
Rhabdomyolysis, or rhabdo, is a fast breakdown of muscle whose contents can harm the kidneys. After spin classes it mostly affects the thighs, a few days after a first class. Most people recover fully: in the review of 97 cases none had lasting harm, and in the Singapore series only 1 of 93 had kidney injury, which settled the next day. Our rhabdomyolysis guide covers it in full.
Muscle pain, swelling or weakness far worse than the class explains, and dark pee (red, brown, tea or cola coloured), sometimes starting hours or days later. Get medical help the same day: call NHS 111, or go to A&E (accident and emergency) if you feel very unwell. Call 999 for sudden, severe pain in a swollen, tight muscle. This is our rhabdomyolysis guide's advice, built from the NHS pages on blood in urine and acute kidney injury; in the published cases, people reached hospital about 3 days after the class, on average.
A first class at a hard pace, whatever your fitness; heat, dehydration or a recent illness (our rhabdomyolysis guide); sickle cell trait, where case report authors suggest seeing a doctor before a first class; and statins, where our rhabdomyolysis guide explains that the NHS says to call NHS 111 for muscle cramps, severe pain and weakness on atorvastatin.
As Spinning (1 November 2018) and Keiser (undated) publish it; their effect on injuries hasn't been measured.
Stand beside the bike: Spinning lines the top of the saddle up with your thigh lifted to 90 degrees, and Keiser with the top of your hip bone. Sitting on it, your knee should keep a slight bend at the bottom of the stroke, about 25 to 35 degrees in both brands' guides, never locked straight. Our cycling page quotes a review that suggests 25 to 30 degrees, with little injury data behind any target.
With the pedals level, your forward kneecap should sit over the pedal spindle, with the ball of your foot over it too (Spinning), or the front of your knee in line with the centre of the pedal (Keiser).
About level with the saddle, "or higher if you feel any discomfort in your back" (Spinning), or slightly higher than the saddle to start, then adjusted so your spine stays neutral (Keiser). Keep a slight bend in your elbows.
Put the widest part of your foot in the toe cage and tighten the strap (Keiser). To stop the flywheel, press down on the resistance knob (Spinning and Peloton).
Formulas for saddle height suited women less well than their own preferred height, so adjust by feel, photograph your settings, and change one thing at a time if something hurts (our suggestion).
Source 42
Borrowed from our cycling page: none of this has been studied in spin classes.
Our cycling page: genital numbness or tingling that settles soon after the ride is a saddle problem, so stand up more, raise the bars or try another saddle. New loss of feeling around your genitals or bottom, changes in bladder or bowel control, or numbness in both legs needs 999. Padded cycling shorts are a common suggestion, not studied in spin classes (our reading).
Change your hand position often and keep a slight bend in your elbows; if numbness or weakness lasts after you stop riding, see a GP (our cycling page).
Tingling feet can come from straps done up too tightly (our reading), so loosen them. The NHS advises seeing a GP if you have pins and needles all the time or they keep coming back.
Source 56
Raise the bars if your back hurts, as Spinning advises, look ahead with your eyes rather than tipping your head right back, and build back endurance (our cycling page and mobility routine for cyclists).
Source 11
The NHS says it's not recommended to start a new vigorous activity in pregnancy, and it calls spinning classes very vigorous. If you already ride, tell the instructor, ride easier, drink water, keep cool, and stop if you feel uncomfortable, too hot or unwell. Our pregnancy guide lists a static bike among good choices; at an easy effort it suits women new to spinning (our reading).
Get advice at your 6-week check before high-impact exercise, and expect a longer recovery after a complicated delivery or a caesarean. Our postpartum guide suggests a static bike from about weeks 4 to 6 and a spin bike from about weeks 8 to 12 if it's comfortable; saddle discomfort after a vaginal birth is a reason to wait (our reading).
Source 58
Young children's fingers get caught in chains, sprockets and flywheels, sometimes with amputations, and most children's stationary bike injuries happen when nobody is riding. The doctors who treated them advise no access for children to any exercise bike, in use or not.
Keep children under 14 and pets away from the bike at all times, give over-14s supervision or instruction, use the resistance knob as an emergency brake, and keep within the 135 kg maximum user weight.
Source 15
A spin class measures 9.0 METs in the Compendium. Spin has no impact, which suits sore joints, injured runners and heavy training weeks; running loads your bones and trains running itself, as our running page explains (our reading).
Source 1
They depend on your effort and your size, not the activity's name; our calories calculator does the sum.
The one you'll keep doing; many people do both. Keep hard spin and hard running sessions on different days (our suggestion).
Built on our warm-up guide, our strength workout for cyclists, our mobility routine for cyclists and our cardio intervals workout (editorial): no spin warm-up has been tested. If the class's own warm-up is shorter than 8 minutes, come early and ride steps 4 to 6 first.
Loading the 3D figure…
The movement on the figure: Stationary cycling
Riding, heavy leg work, hops for bone, and the back, neck and shoulders that hold a riding position. Each has a 3D demo.
3D demoStationary cyclingBeginner · Cardio machine
3D demoDumbbell goblet squatIntermediate · A dumbbell
3D demoRear-foot-elevated split squat (Bulgarian split squat)Intermediate · A bench or box
3D demoDumbbell Romanian deadliftIntermediate · A dumbbell
3D demoSingle-leg calf raise from a stepIntermediate · A step + A wall
3D demoPogo hopsIntermediate · No equipment
3D demoHeel drop (impact for bone)Beginner · No equipment
3D demoSupported single-arm dumbbell rowIntermediate · A dumbbell + A bench or box
3D demoSide plankIntermediate · No equipment
3D demoBird dogBeginner · No equipment
3D demoProne Y-T-W raisesBeginner · No equipment
3D demoChin tuckBeginner · No equipment
3D demoHalf-kneeling hip flexor stretchBeginner · No equipment
3D demoDoorway chest openerBeginner · A wallThe first two are new: a strength workout for riders and a first ride at your own pace. The rest add cycling strength and mobility, intervals, easy rides, knees, neck and shoulders, bone, and a light return after rhabdomyolysis.
A 45-minute dumbbell session for riders: easy cycling, hops or heel drops, squats, split squats, Romanian deadlifts, calf raises, rows, back and neck work.
45 minIntermediate16 movesCardio machine, A dumbbellA 35-minute first indoor cycling ride at your own pace: set up the bike, warm up for 8 minutes, ride short steady efforts and climbs, then cool down easily.
35 minBeginner4 movesCardio machine, A wallA 50-minute gym session for cyclists: heavy squats, one-leg presses, hip flexion and calf raises as in the cycling trials, plus jumps for bone.
50 minIntermediate13 movesCardio machine, A barbellA 15-minute routine for cyclists: hips, upper back, chest, neck and wrists through the ranges riding doesn't use, plus back and neck endurance.
15 minBeginner12 movesA foam roller, A wallA 25-minute interval session on a bike or rower: one-minute hard efforts with two minutes easy, building from 4 to 8 rounds.
25 minIntermediate1 movesCardio machineThe Norwegian 4x4, a well-studied interval session for raising VO2 max: four 4-minute hard efforts with 3 easy minutes between, on a bike, rower or treadmill.
40 minIntermediate3 movesCardio machine, A wallA steady 30 to 45 minute cardio session at talk-but-not-sing pace: walk, cycle, row or cross-train, counting toward weekly activity guidelines.
40 minBeginner3 movesCardio machine, A wallThe cycling session from a migraine trial: 15 minutes of gently building warm-up, 20 minutes at a fairly hard effort and 5 minutes easy, 3 times a week.
45 minBeginner4 movesCardio machine, A wallA beginner brick: an easy then a steady ride, a calm change of shoes, 10 to 15 minutes of easy running, then a walk and calf and hip stretches.
50 minBeginner5 movesCardio machine, A wallA 25-minute session for knees that don't currently hurt: thigh and hamstring strength, single-leg control, then an optional full-range block with knees over toes.
25 minBeginner13 movesA bench or box, A wallDeep neck holds and shoulder-blade strength in under 20 minutes: one of the best-supported kinds of exercise for a stiff, sore neck.
18 minBeginner11 movesA band, An anchor pointA 12-minute routine for a stiff upper back and rounded shoulders: chin tucks, wall angels, Y-T-W raises and open books.
12 minBeginner8 movesA foam roller, A wallWrist mobility and forearm strength for desk work, climbing, push-ups and handstands.
10 minBeginner7 movesA wall, A dumbbellImpact, strength and balance for stronger bones, following UK osteoporosis consensus advice, with options for every level.
40 minBeginner14 movesA kettlebell, Other / check instructionsA 40-minute strength workout for runners at home: hops, Bulgarian split squats, single-leg deadlifts, step-ups, calf raises and side planks.
40 minIntermediate15 movesA wall, A bench or boxA 30-minute light session for the first weeks back after rhabdomyolysis: easy cycling or walking, Pilates-style moves and light strength, never to failure.
30 minBeginner15 movesCardio machine, A bench or boxA 10-minute cool-down for after a run, a class or a gym session: a few minutes of easy movement, stretches for the muscles you used, then slow breathing.
10 minBeginner9 movesCardio machine, A wallOne or two spin classes a week fit around two strength days.
A full week that mixes intensities: three strength days, two cardio days, a mobility day and an easy day, never seven hard days.
3 training days45 minBeginner5 days a weekA 12-week workout plan for weight loss: three strength days, two cardio days and daily steps, building to 200 minutes a week, with honest results.
3 training days45 minBeginner2 days a weekTwo full-body strength sessions a week: the minimum that meets health guidelines, with every set, rep and rest, and an 8-week progression.
2 training days45 minBeginner3 days a weekThree full-body home workouts a week with dumbbells or no equipment at all, plus walks and an 8-week plan to keep progressing.
3 training days35 minBeginner2 days a weekA 12-week strength plan for runners: two sessions a week of heavy lifts, single-leg work, calf raises and hops, fitted around your runs.
2 training days45 minBeginnerThe PAR-Q+ (Physical Activity Readiness Questionnaire for Everyone) asks about a heart condition or high blood pressure, chest pain, dizziness or losing consciousness, other long-term conditions and their medicines, a bone or joint problem that activity could make worse, and being told to exercise only under supervision. If you answer yes to any, check with your doctor or a qualified exercise professional first, and wait if you're ill. If you're over 45 and not used to vigorous exercise, it advises speaking to a qualified exercise professional before working that hard.
Source 59
Most rhabdomyolysis cases follow a first class, and fitness didn't protect. Ride our first spin class ride or a beginners' class at your own pace.
Case report authors suggest seeing a doctor before your first spin class. Our sickle cell guide explains more.
Source 30
Our rhabdomyolysis guide explains that the NHS says to call NHS 111 if you take atorvastatin and get muscle cramps, severe pain and weakness. Don't stop a statin without talking to your doctor.
The NHS calls spinning classes very vigorous. Check first if the PAR-Q+ says so; our HIIT guide advises checking with a GP first if you're inactive with heart, metabolic or kidney disease, or have symptoms when active. Start with steady riding, as our zone 2 guide describes.
Check your blood sugar before and after: hard efforts can raise it for a while and lower it later, as our cardio intervals workout explains.
Drink first, choose a cool room, and ease off for longer at the end rather than stopping dead, as our cool-down guide explains.
Don't start spinning as a new vigorous activity in pregnancy. If you already ride, tell the instructor, ride easier and keep cool.
Source 57
Get advice at your 6-week check; our postpartum guide suggests a spin bike from about weeks 8 to 12 if it's comfortable.
Source 58
Stationary cycling eased pain in trials, at a lower intensity than a class, so start with easier rides (our reading).
Source 51
Classes are often very loud. Wear ear plugs and choose a bike away from the speakers.
Our light session for the first weeks back after rhabdomyolysis comes first, and new classes come back last.
Muscle pain, swelling or weakness far worse than the class explains, and dark pee (red, brown, tea or cola coloured), sometimes starting hours or days later, need medical help the same day: call NHS 111, or go to A&E (accident and emergency) if you feel very unwell. Call 999 for sudden, severe pain in a swollen, tight muscle (our rhabdomyolysis guide). The NHS says blood in pee may be "bright pink, red or dark brown", and lists peeing a lot less than usual, feeling very thirsty, feeling or being sick, and swollen feet or legs among the symptoms of acute kidney injury.
The NHS says to call 999 if:
Call 999 if someone faints while exercising. If you feel faint, lie down with your legs raised, or sit with your head lowered between your knees.
Source 61
Call 999 if someone is still unwell after 30 minutes of resting somewhere cool, being cooled and drinking fluids, or has a very high temperature, hot skin that isn't sweating, a fast heartbeat or breathing, confusion or poor coordination, a fit, or loses consciousness.
Source 44
Call 999 or go to A&E for signs of dehydration with blue, grey, pale or blotchy skin, lips or tongue, skin that feels cold, difficulty breathing or lots of quick breaths, confusion, or being sleepier than normal or difficult to wake.
Source 62
Call 999 or go to A&E for new loss of feeling around your genitals or bottom, changes in your bladder or bowels, or tingling, weakness or numbness in both legs, especially with back pain.
Source 63
Ask for an urgent GP appointment or get help from NHS 111 for sudden hearing loss in one or both ears. Go to A&E or call 999 for tinnitus with sudden hearing loss, weakness in the muscles of your face, or a spinning sensation (vertigo).
The NHS says to stop if you feel uncomfortable, too hot or unwell. Our pregnancy guide adds: stop and call your midwife or maternity unit if you have bleeding, fluid leaking, regular painful contractions, chest pain, dizziness, or calf pain or swelling.
Source 57
At the Compendium's 9.0 METs, a 70 kg rider uses about 470 kcal in 45 minutes (our arithmetic), a lighter rider less, and calculators can't know your effort.
Source 1
Cases followed a first session "regardless of the degree of previous physical training", and one was in a young person who exercised regularly.
It follows sessions that are too much, too fast or too new for you, often a first class, and symptoms can start hours or days later: in the published cases, people reached hospital about 3 days after the class, on average.
Source 4
Case series' authors advise a gradual start with good hydration, but no study shows that fluids prevent it, and our rhabdomyolysis guide says dehydration adds to the risk but rhabdo happens without it.
One cross-sectional survey, read as an abstract, linked spinning classes with knee injuries in women, but stationary cycling eased knee osteoarthritis pain in trials. Set-up matters.
Classes about 3 decibels quieter felt just as hard, and many riders preferred the music quieter.
Yes, and it's hard: the Compendium of Physical Activities gives a spin class 9.0 METs (metabolic equivalents), and the NHS calls spinning classes very vigorous. Sedentary women who went about 2.6 times a week for 12 weeks raised their exercise capacity by 16%.
It can be harder than it feels: in one study, riders spent a third to a half of a class above the point where breathing gets hard. You control the resistance, so ride at your own pace, especially in your first few classes.
Rhabdomyolysis is a fast breakdown of muscle that can harm the kidneys. In 97 published cases after indoor cycling, most were healthy women at their first class; they reached hospital about 3 days later on average, and none had lasting harm. Dark pee with muscle pain far worse than normal soreness needs medical help the same day.
Set the saddle level with your hip bone, or with the top of your thigh when you lift it to 90 degrees, so your knee keeps a slight bend at the bottom of the stroke. With the pedals level, your kneecap should be over the pedal spindle; set the bars level with the saddle, or higher if your back hurts.
It depends on your size and effort. At the Compendium's 9.0 METs, a 70 kg rider uses about 470 kcal in 45 minutes (our arithmetic), and our calories calculator does the sum for you.
Saddle soreness is common when you start, though no study has measured it in spin classes. Stand for a few pedal strokes every 10 minutes and check the saddle position; numbness that doesn't settle soon after the ride, or new loss of feeling around your genitals or bottom, needs action.
A saddle that's too low or too far forward, or too much resistance too soon, are the usual suspects, though the evidence is borrowed from cycling, and one survey linked spinning with knee injuries in women. Check the set-up, ease the resistance and see our knee pain guide if it doesn't settle.
A review of 13 small studies recommended combining indoor cycling with diet to lose weight. Exercise alone takes off about 2 to 3 kg on average; spin's bigger win is fitness.
The NHS says not to start a new vigorous activity in pregnancy. If you already ride, tell the instructor, ride easier, keep cool and drink water; if you're new to it, an easy ride on a static bike is one of our pregnancy guide's suggestions.
Neither is better; both are good cardio. Spin has no impact, which suits sore joints and heavy training weeks, while running loads your bones and trains running itself, so many people do both.
Exercise education for people who play sport, not a personal prescription or a diagnosis, and clinical review of these pages is pending. Check with a GP or physiotherapist before hard training if you have a heart condition, chest pain, dizziness or an injury that isn't settling, and stop for sharp or increasing pain. Health disclaimer.
