Cramp During Exercise: Why It Happens and What Helps
You finally get 45 minutes to yourself, you are halfway through a set of lunges, and suddenly your calf locks into a hard, painful knot. You stop, hop about, swear quietly and wonder if you have done something serious. Getting cramp during exercise is common, it is usually harmless, and there are a few simple things that can make it less likely. This guide explains what is going on, how to ease a cramp in the moment and the habits that may help, based on NHS guidance and what I see coaching tired parents in Archway.
What is cramp, exactly?
A cramp is a sudden, involuntary tightening of a muscle. It often hits the calf, the back of the thigh (hamstring) or the foot, and it can last anywhere from a few seconds to several minutes. The muscle may feel hard to touch, and it can be sore for a while afterwards.
The NHS page on leg cramps lists several possible causes, including:
- Straining a muscle during exercise, which can be worse in hot or humid weather
- Dehydration
- Pregnancy, usually in the later stages
- Some medicines, such as statins and diuretics
- Getting older
The NHS also says that sometimes there is no clear cause at all.
How to ease cramp during exercise in the moment
When a cramp grabs you mid-workout, the aim is to gently lengthen the muscle and get weight back through it. Here is what I tell people in my classes to do:
- Stop the exercise. Do not push through the set.
- Stretch the muscle gently. For a calf cramp, straighten the leg and pull your toes up towards your shin, or stand and lean into a wall with the cramped leg straight behind you and the heel down. For a hamstring cramp, straighten the leg on the floor and hinge forward slightly from the hips.
- Stand and put weight on it. The NHS notes that standing and putting weight on the leg may help. Walk slowly for a minute once it starts to let go.
- Massage it. Firm, slow rubbing along the muscle can help it relax.
- Sip some water and rest. Give it a couple of minutes before deciding whether to carry on. If it keeps coming back, call it a day.
The muscle may feel tender for a day or two. That is normal. My post on muscle soreness after exercise explains how that differs from normal post-workout aches.
Habits that may help prevent it
1. Warm up properly
Most cramps I see in class happen to people who rushed in late from the school run and went straight into the hard part. Five to eight minutes of easy movement (marching, arm circles, bodyweight squats, gentle lunges) gets blood into the muscles and prepares them for work. Here is my simple warm-up before exercise if you want a routine to copy.
2. Drink through the day, not just in the session
If you have had two coffees and nothing else since breakfast, you are more likely to start a workout a bit dry. Keep a water bottle on the go during the day. The NHS dehydration page lists signs like dark yellow, strong-smelling pee and feeling dizzy or tired. My post on signs of dehydration goes into this in more detail for busy parents.
3. Build up gradually
Muscles that are asked to do far more than they are used to are more likely to cramp. If you have not trained for months, start with fewer sets and shorter sessions and add a little each week. Doing 20 jump squats on day one is how a lot of calf cramps start.
4. Be careful in the heat
Hot, stuffy rooms and summer heat both seem to make cramp more common. On warm days, slow the pace, take more breaks and drink more.
5. Stretch your calves daily if you get night cramps too
If you also get cramps in bed, the NHS suggests a simple calf stretch. Stand facing a wall with your hands on it and feet flat, lean forward until you feel the stretch in your calves, hold for a couple of seconds, stand back up and repeat for about 5 minutes, up to three times a day, with the last one just before bed. It takes less time than brushing your teeth.
A simple anti-cramp routine to try
Here is a short routine you can do before a run or a class, or on its own on a quiet evening:
- Wall calf stretch: 3 x 30 seconds each leg, back knee straight
- Bent-knee calf stretch: 3 x 30 seconds each leg, back knee slightly bent to reach the lower calf
- Calf raises on a step: 2 sets of 12, slow on the way down
- Lying hamstring stretch with a towel: 2 x 30 seconds each leg
The calf raises matter: a stronger calf copes better with extra work.
When to get cramp checked
Occasional cramp during a hard session is not usually a worry. But the NHS advises seeing a GP if cramps are disrupting your sleep, last longer than 10 minutes, or come with numbness or swelling in your legs. If you are pregnant, on regular medication, or have any condition you are unsure about, check with your GP or a physio before changing your exercise routine. And if a “cramp” came on with a sudden sharp pain, like being kicked in the back of the leg, stop and get it looked at, as that can be a different kind of injury.
How bootcamp classes fit in
In my classes we always start with a proper warm-up, the pace builds gradually, and every exercise has an easier and harder option. If your calf starts to tighten, you can step out, stretch and drop to the easier version without anyone making a fuss. The church hall in Archway is indoors, so you are not training in freezing rain one week and baking sun the next. If you want a class that focuses on moving well rather than going flat out, SYP Recharge is a good place to start.
FAQs
Does a banana stop cramp?
Bananas are a good snack, but there is no strong evidence that eating one before training prevents cramp. Warming up, building up gradually and staying hydrated are more useful habits.
Should I keep exercising after a cramp?
If it eases completely after stretching and walking, you can usually carry on gently. If it keeps returning or the muscle feels injured rather than tight, stop for the day.
Why do I cramp in my foot when I exercise?
Foot cramps are common in people who are new to barefoot or flat-shoe training, or who wear tight shoes. Toe spreads, towel scrunches and properly fitting trainers can help. If it is frequent, mention it to your GP.
Book your first class
If you want to get fitter without throwing yourself in at the deep end, come and try a session. SYP Bootcamp runs 45-minute small-group classes in a church hall in Archway N19, with a maximum of 10 people and every exercise scaled to your level, for £15 a class. Book your £15 class here or call or WhatsApp me on 07301 512215 and I will send you the timetable. If you would rather start one to one, you can see how personal training with me works.
About the author
Artem Olekhnovych is a personal trainer in Archway and the founder of SYP Fitness and SYP Bootcamp. He has coached clients in Archway, Highgate and across North London for over 10 years, and runs small-group bootcamp classes for busy mums and dads. Read reviews from his 1-1 clients.
