Stop and get medical help
For chest pain or pressure, unusual breathlessness, dizziness or fainting, or a racing or irregular heartbeat during exercise, as our plans advise. The American Heart Association says these need immediate medical evaluation.
Source 10
Call 999 (911 in the US)
For sudden chest pain or discomfort that doesn't go away, pain that spreads to your arms, neck, jaw, stomach or back, or chest pain with sweating, feeling sick, light-headedness or breathlessness; someone who faints while exercising; palpitations that don't go away, or come with chest pain, breathlessness or feeling faint; a headache that starts suddenly and is extremely painful, for example during a heavy set; or the signs of a stroke, even if they've stopped. Don't drive yourself to A&E.
Sources 32, 33, 34, 35, 36, 37
Muscle breakdown after a big session
Same day (call NHS 111, or go to A&E if you feel very unwell): after a big or unusual session, such as hundreds of thrusters or wall balls, or a benchmark workout done for time, muscle pain, swelling or weakness far worse than the session explains, and dark pee (red, brown, tea or cola coloured), sometimes starting hours or days later. Dark pee isn't always there, so muscles far sorer, more swollen or weaker than the session explains still need the same-day check. It can be rhabdomyolysis, a breakdown of muscle that can harm the kidneys; in one hospital, 6 of 11 people who had it after CrossFit were beginners. Call 999 for sudden, severe pain in a swollen, tight muscle, as our pain guides advise.
Sources 38, 39, 40
Your shoulder
Call 999 or go to A&E if, after a fall or the weight coming down on you, your shoulder looks out of place or has changed shape, or you can't move your arm; don't try to put it back in yourself. Ask for an urgent GP appointment or get help from NHS 111 for sudden or very bad shoulder pain, pins and needles that don't go away, or severe pain in both shoulders. See a GP or physiotherapist if shoulder pain is getting worse or hasn't improved after 2 weeks of looking after it yourself, or if your shoulder has partly or fully come out of joint, or you worry it might.
Sources 41, 42
Your wrist
Contact NHS 111 for severe wrist pain, a snap, grinding or popping noise when it happened, a wrist you can't move or hold things with, one that has changed shape or colour, or lost feeling in your hand. See a GP if wrist pain hasn't improved after 2 weeks of looking after it at home, is getting worse, keeps coming back or stops your normal activities.
Source 43
Your back or knees
Call 999 or go to A&E for back pain with pain, tingling, weakness or numbness in both legs, loss of feeling around your genitals or bottom, new trouble peeing or controlling your bladder or bowels, or changes in genital sensation during sex. Get advice from NHS 111 if your knee is very painful, you can't put weight on it, it's badly swollen or has changed shape, or it locks or gives way.
Sources 44, 45
A hernia
See a GP if you think you have a hernia. Get help from NHS 111 for pain in or around it, a bloated tummy, being sick, constipation, a high temperature or sudden confusion. Call 999 or go to A&E for a femoral hernia (a lump at the top of the thigh) with very bad tummy pain, being sick, being unable to fart or poo, a high temperature or sudden confusion.
Sources 46, 47
Check before you start
If you haven't exercised for some time or have a medical condition, speak to your GP first, as the NHS advises. Check with your GP before hard intervals if you're inactive and have heart, metabolic or kidney disease, or symptoms when you're active, as our HIIT guide says.
Source 48