How hard: the talk testStrong evidence
Do most of your running at a pace where you can still talk in full sentences. In small lab studies, the point where talking first got harder matched the first breathing threshold, and the talk test used on its own kept 30-minute runs at a steady training pace.
Health guidance lists running as vigorous activity, but effort is personal. On a 0 to 10 scale of how hard it feels to you, moderate effort is 5 or 6, where you can talk but not sing, and vigorous starts at 7 or 8, where you can say only a few words without pausing for breath. Down to short sentences on an easy day? Slow down, or walk for a minute.
In this plan, every swim, ride and run is at a pace where you can talk in full sentences, apart from the short faster bursts on Thursday's ride from week 6 and the race-effort bursts in weeks 11 and 12, which are short sentences only.
Sources 1, 2, 3, 4, 5, 6
Build up one run at a timeEmerging evidence
No weekly percentage rule has been shown to prevent injuries. In 532 new runners, a slower 13-week programme built on the "10% rule" injured as many people as a standard 8-week one (20.8% against 20.3%), and a review of trials found no evidence that a more gradual build prevents injuries.
In one study that followed 5,205 runners, mostly men around 46 with years of running behind them, a run more than about 10% longer than their longest run of the past month went with more injuries, while week-to-week changes in total distance didn't. That's an association, not a tested rule.
So Wednesday's longer run grows by under 10% at a time, from 25 to 40 minutes, the brick's run replaces Sunday's run, and the rides and swims build the same gradual way (our suggestion).
Sources 7, 8, 9
Warm up by walking and jogging; stretching is optionalEmerging evidence
Start every run with 3 to 5 minutes of brisk walking, then ease into an easy jog: the NHS suggests 5 to 10 minutes of brisk walking or gentle jogging before you run. Before hills, intervals, tempo runs, time trials and races, add the drills and strides in each session: across 32 studies, warm-ups other than stretching improved performance in 79% of the results measured. Walk or jog easily for 3 to 5 minutes at the end.
Stretching hasn't been shown to prevent running injuries: in pooled trials it didn't reduce them. Stretch afterwards if it feels good.
Sources 10, 11, 8
Aches, pain and when to stopEmerging evidence
Stiff, achy legs for a day or two after a long run or a hard session are normal. Stop and rest if a pain is sharp, makes you limp or change how you run, or builds as you go, and skip your next run if it's worse the next morning. The NHS advises not running when you're in pain, and seeing a GP or physiotherapist if it doesn't go away; a very painful or swollen knee, or a sudden sharp pain at the back of the ankle, needs a GP straight away.
Pain in one spot on a bone that hurts to press, gets worse with each step and later aches at rest or at night can be a stress fracture: stop running and get it checked. When you can walk briskly without pain, restart a week or two back in the plan. In one study, injured new runners took a median of about 10 weeks to recover, so it pays to stop early.
Our guides to knee, hip, foot and lower back pain when running show what to change and how to build back.
Sources 10, 12, 13
Stop and get helpStrong evidence
Call 999 in the UK or 911 in the US for chest pain that feels tight or like squeezing, or spreads to your arms, neck, jaw or back; chest pain with sweating, feeling sick, light-headedness or breathlessness; or severe difficulty breathing. Don't drive yourself to hospital. If someone stops responding and stops breathing, call and start cardiopulmonary resuscitation (CPR).
Call NHS 111 (in the US, your doctor or an urgent care centre) if you're suddenly more short of breath than usual, or have chest pain with feeling sick or a heartbeat that races, skips or flutters.
In the heat, tiredness, dizziness, a headache, feeling sick, heavy sweating and intense thirst can be heat exhaustion: stop, get somewhere cool, drink and cool your skin, and you should feel better within 30 minutes. If you don't, or there's confusion, hot skin that has stopped sweating, a fit or a collapse, call 999 or 911: that's heatstroke.
In the water: sudden breathlessness, coughing, or frothy or pink spit can be fluid on the lungs (swimming-induced pulmonary oedema). Stop, roll onto your back, raise an arm for the safety crew and get out, and call 999 or 911 if it doesn't settle quickly (our suggestion). Shivering, numbness, confusion or slurred speech after a swim can be hypothermia: get the person somewhere sheltered, out of wet clothes and wrapped up, and go to accident and emergency (A&E) or call 999 or 911 if you think someone has it.
Sources 14, 15, 16, 17, 18, 19, 20
Missed sessions and breaks
Missed a session? Carry on where you left off; don't double up. Missed a week or more, or been ill? Repeat the last week you completed, or go back two (our suggestion). Repeating weeks is part of the plan, not a failure.
Shoes and kitStrong evidence
Wear running shoes that fit and feel comfortable. No type of running shoe has been shown to prevent injuries, and choosing shoes by foot shape made no difference in three trials of more than 7,000 military recruits. In 927 new runners in neutral shoes, feet that roll in weren't injured more often over a year.
On the bike, World Triathlon's rules require an approved helmet, and in studies of injured cyclists, helmets went with about half the odds of a head injury. Check your brakes and tyres before every ride, and use lights in poor light.
Sources 21, 22, 23, 24
Check first, and who should start elsewhereStrong evidence
Answer the 7 questions of the Physical Activity Readiness Questionnaire (PAR-Q+) before you start. A yes to any (a heart condition or high blood pressure, chest pain, dizziness or fainting, another long-term condition or its medicines, a bone or joint problem, or being told to exercise only under medical supervision) means checking with your doctor or a qualified exercise professional first. It also asks people over 45 who aren't used to hard, all-out effort to check before exercising that hard: think races, time trials and intervals, not easy runs. Wait if you have a cold or a fever. The NHS suggests speaking to a GP first if you have medical conditions or concerns.
US guidance says people without conditions or symptoms don't need to see a doctor first, and that people who are already active can step up to vigorous training without doing so; new symptoms as you step up mean seeing a doctor. Screening advice from the American College of Sports Medicine likewise turns on how active you are, any symptoms or known heart, metabolic or kidney disease, and how hard you plan to train.
Not these plans, or not yet: myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS), where our ME/CFS exercise guide is the place to start; and pregnancy, unless you were already running or training hard, because the NHS advises against starting a new vigorous activity such as running.
Before open water, read the note on your heart and lungs below: in US races, most deaths and cardiac arrests happened in the swim. World Triathlon's minimum age for a sprint triathlon is 16.
Sources 25, 5, 6, 26, 27, 28, 24