Experts issue warning to anyone who exercises: ‘It’s not always the hero we think it is’

Hitting the gym several times a week, weight training, running, spinning and swimming are all -based activities millions of Brits enjoy.

Regular exercise improves  lowers  and , fight wrinkles, and help beat .

Many of us are still determined to stick to our new year resolution of being more active, personal trainers and exercise experts are warning us to beware of some of the less pleasant side effects of exercising.

Freddie Chatt, a fitness expert, instructor, and founder of Village Cricket, said exercise can do wonders for health. He said: “But there are times when it’s not the hero we think it is. It can actually make some things worse or cause problems that people don’t always expect. I’ve seen this happen plenty of times in my work, and it’s not always obvious at first.”

Chatt said some side effects may be a sign of an undiagnosed health condition, but they are more likely to be simply a case of either overdoing it or not eating or drinking enough of the right foods.

If you are worried about your health or you are thinking of exercising, always check with your GP first.

Exercise-induced headaches

Personal trainer Luke Hughes of Activecareers said headaches post- or during exercise were a common experience among gym goers.

There are two types of headaches: an exertional headache and a tension headache. “An exertional headache is often described as a pulsing sensation or pain that runs down each side of the face and can occur if you’re dehydrated or have an underlying health concern, which is ignited when exercising.”

Adam Clark, a fitness expert from Rugbystuff.com, said aerobic exercises and weightlifting were both potential triggers of exertion headaches.

He said: “Scientists have not been able to pinpoint exactly what causes them, but they think it may be the result of blood vessels in your brain widening as you exercise. 

“If you have other symptoms accompanying the headache, such as vomiting, fainting, double vision or neck stiffness, this can suggest that there is something more serious happening and you should seek medical attention.

Nataly Komova, a registered dietician and personal trainer, said headaches when exercising can also be caused by dehydration, an electrolyte imbalance, low blood sugar, heat exhaustion, overexertion or even environmental factors like high altitudes or strong smells.

Heatstroke or hypothermia after exercise

Clark said it was not unusal to shiver after exercise and was a common sign of muscle fatigue or low blood sugar.

“Most often, shivering or muscle shakes after a workout suggest that you are not yet used to the level of intensity of the exercise you just did, and your body cannot support this exertion without becoming fatigued. As your muscles are able to rest or you eat something, the shivering should eventually begin to stop. To prevent shivering, lower the intensity of exercise until you feel strong enough to push yourself more, and do not exercise on an empty stomach.”

Exercising can also pose the risk of heat stroke or heat exhaustion if you overexert yourself. Symptoms to look out for include dizziness, nausea, muscle cramps, and more frequent sweating.

Exercise addiction and overtraining.

It is possible to become addicted to exercise, and feeling guilty when you do not work out daily can be a sign of overdoing things.

Hughes said feeling the need to constantly exercise can lead to overtraining. He said: “The mental damage can be worse as people feel the need that they must improve and their mental wellbeing can hinge on their ability to train well. Additionally, it can lead to things like body and muscle dysmorphia as well as eating problems.”

Peter Day, an athlete and Lifespan Fitness expert, said overtraining can lead to chronic injuries, hormone imbalances, weakened immunity, and a loss of motivation. He said: “Most importantly, it can prevent you from seeing the results you want, which is counterproductive to your fitness journey.” 

Premature ageing 

When you exercise intensely, normally for a long period, your body harnesses fat stores and burns sugars.

Hughes said: “As part of this process, your body produces free radicals, which in turn can bind with cholesterol in a process called ‘oxidative stress’. This can lead to concentrated amounts of plaque building up in your system and thus causing clogging of arteries and blood vessels.”

Diabetes

He added that increased consumption of nutritional supplements to support muscle growth, repair, and performance can lead to diabetes.

He said: “Many fitness-based supplements contain large amounts of sugar alcohol and artificial sweeteners, which can cause damage to your blood vessels.

“This can put you at risk of developing type II diabetes as your muscle receptors become more accustomed to elevated insulin levels.”

Recurring Injuries

Hughes said one of the most obvious negative effects of exercise is recurring injuries, micro-traumas, or chronic issues. He continued: “This can lead to time away from exercise and training that can accumulate into months or even years of rehabilitation, physiotherapy or even the necessity for surgery.”

Gout

Nataly Komova said intense exertion can temporarily elevate uric acid, which causes gout.

She said: “Exercise might trigger a flare-up although it’s rarely the sole instigator. I’ve observed that consistent, moderate activity, coupled with proper hydration and diet, can actually mitigate gout symptoms by enhancing overall metabolic function. I believe the focus should be on tailoring exercise to individual metabolic capacities, not complete avoidanc

Chatt said: “If someone already struggles with gout, pushing too hard during exercise isn’t going to help. Gentle, consistent movement is usually better in that case, and anything too strenuous during a flare-up should be avoided.”

Hives

Going from hot to cold, for example an early morning spin class in the middle of winter can cause symptoms of hives,.

Komova said this is known as cold urticaria and is the body’s immune system reaction to environmental shifts, specifically rapid temperature changes. “I’ve observed a higher prevalence in individuals with other allergic tendencies. The sudden warming after cold exposure, I believe, triggers histamine release, causing the characteristic hives. I advise layered clothing, avoiding drastic temperature shifts, and protective balms.”

Insomnia and exercise

Exercise is supposed to help with sleep, but there is a danger it can lead to the opposite effect.

Day said overtraining can interfere with sleep patterns, making it difficult to fall asleep or experiencing poor-quality sleep. Intense exercise increases cortisol levels, a stress hormone, which can make it difficult for the body to wind down. 

“Over time, sleep deprivation can exacerbate the negative effects of overtraining, and in turn, can be damaging to your mental and physical health.”