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Fitness hangovers: what do post-workout headaches and nausea mean?

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A ‘fitness hangover’ is the term for when your workout leaves you feeling knackered, sick and headachey. But why do some people get them? 

One of the most commonly touted benefits of exercise is the post-workout endorphins rush. When you can’t be bothered – or feel a bit off your game – the promise of these happy hormones pumping through your body is often enough to get you through your training

But what happens when your workout leaves you feeling worse than when you started? According to a study by American supplement brand Lifeaid, ‘fitness hangovers’ are a real thing – and they’re impacting a huge amount of regular exercisers

We’re not just talking about those small, expected side effects that come from training, such as DOMS. According to the study, fitness hangovers can include soreness that stops people from participating in other life and work activities, just as an alcohol-induced hangover does. Researchers also found that 29% of respondents skipped out on work and 55% stayed inside all day due to extreme soreness, and many people suffered long-term injury – including ankle sprains and knee strains

However, there are other symptoms being reported by other fitness hangover sufferers, including exhaustion, nausea, and headaches. “After a long run (more than 10 miles for me), I’ll often suddenly feel like I’m hungover,” says Strong Women editor Miranda Larbi. “I’ll get a headache, be really lethargic and sometimes it’ll even last until the morning after. I think it’s from not refuelling properly as I completely lose my appetite after running – all the blood goes to your muscles and away from your stomach – and a bit of dehydration.”

According to Dr Leila Dehghan, a medical doctor, personal trainer and nutritionist, “there isn’t a clear definition for fitness hangover. Some people refer to delayed muscle soreness (DOMS) as a fitness hangover, but the symptoms can also be severe pain, extreme tiredness, weakness and nausea up to 24 hours post-workout.”

A woman sat on the floor feeling tired and sick after exercising
Fitness hangover: Feeling fatigued or sick after exercise isn't a good sign.

Why do I feel so awful after working out?

There are many biological reasons as to why exercise might make us feel a bit worse for wear, according to Dr Dehghan. 

“Firstly, during exercise, the glycogen stores in the muscles get depleted. When that happens, the body struggles to maintain blood sugar levels which can result in many feeling light-headed and tired. At the same time, we lose fluid through sweating and, with that, salts. This can cause a drop in blood pressure which can leave people feeling dizzy,” she says.

“The feelings of nausea and lethargy can also be caused by a build-up of lactic acid in muscles. During training, we need more oxygen to break down glucose and produce energy. However, during a strenuous training session, our body cannot meet the increased demand for oxygen and that leads to the production of lactic acid – which can make people feel nauseous, weak, have stomach pain or cramping, burning sensations in the muscles.” 

However, these should all be temporary symptoms and not last after the training has ended. If you’re experiencing them as a ‘hangover’ to your training, it could be a sign of “overdoing exercise, and not looking after yourself properly afterwards. That includes a proper warm-up, cool down and the right nutrition,” says Dr Dehghan. 

“These sensations are your body’s ways of telling you to stop. Having a cramp while running because of lactate build-up means ‘stop and rest’, it doesn’t mean run through the pain. I believe many people who suffer from fitness hangovers because they push themselves too hard and often they ignore the signals from their body that they should stop,” she adds.

How to prevent a fitness hangover?

Adapting your training and nutrition is the first step to avoiding these symptoms. “If you’re new to exercise, don’t overdo it. Start with shorter and lower intensity sessions. Gradually build up to longer or high-intensity exercises,” says Dr Dehghan. Eventually, your body will adapt to training, including building up a greater tolerance to lactic acid and allowing you to train harder without pain

Even if you’re an experienced exerciser, it’s not wise to continue to push your body beyond the point of normal exertion. Not only because it could wipe you out for the whole day, impacting your work and social life, but long-term overtraining can cause physical, hormonal and mental issues. If you are going to be doing a tough session, “begin every workout with a warm-up so that your body has time to adjust to the increased demand,” advises Dr Dehghan. 

“Make sure to drink water to replace the lost fluid and, as far as nutrition is concerned, it’s recommended not to have a heavy meal before any workout but you should have a carbohydrate-rich snack to maintain the glycogen stores during training,” she says. 

A general rule of thumb is that you should fuel your body one to three hours before a workout – “something simple as a banana with a tablespoon of peanut butter as a pre-workout snack will do the trick,” according to Dr Dehghan. 

“Post-workout it’s essential to take time to rest and replace the lost fluids, electrolytes and energy. For most gym-goers it’s enough to have a small snack consisting of carbohydrates and protein (for example, a bagel with peanut butter) and then a high carbohydrate meal within 12 hours post-workout.”

While there’s nothing wrong with a workout that challenges you, “your workout shouldn’t make you dread your next session,” says Dr Dehghan. “A good workout should make you feel happy, elated, and generally better than before you started. You may feel physically tired and even hungry, but you should still have enough energy to finish working out and go about your day.”

Right now, there are enough things going on in the world to make us feel rubbish. Don’t let your workout be another. 

Follow @StrongWomenUK on Instagram for the latest workouts, delicious recipes and motivation from your favourite fitness experts.

Images: Getty

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Chloe Gray

Chloe Gray is the senior writer for stylist.co.uk's fitness brand Strong Women. When she's not writing or lifting weights, she's most likely found practicing handstands, sipping a gin and tonic or eating peanut butter straight out of the jar (not all at the same time).

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