Over-exertion occurs when you push your body beyond its limit for too long. In the workplace it can present as repetitive strains – doing the same movement over and over again leading to such conditions as carpal tunnel syndrome or frozen shoulder. But when over-exertion takes place in sports and exercise it can have very serious – even fatal – consequences.

Recently, I witnessed a case of over-exertion up close. My husband believed that in a month’s time he could get himself in shape for the Death Ride (130 mile long bike ride incl. 5 mountain passes) although he basically hadn’t ridden his bike all year. Now, he used to be in excellent shape and ride a lot, which is probably the most common mistake people make when it comes to over-exertion: Thinking they used to be in great shape, so they will quickly regain their former fitness level regardless of the amount of time that has passed.

My husband took a leave from work at the beginning of June and spent most days on his bike. June had quite a few days with scorching heat, but he had already laid out his training schedule, which was impressive and cruel in terms of load-increase. It also included cutting calories to lose weight. Whenever he was out on the bike, he was good with fluids and knew exactly where the ‘water-stations’ were on his routes. But one evening I got a call to pick him up at a gas station where he was downing bottle after bottle of water, powerade, and vitamin-water, but couldn’t seem to quench his thirst, and he felt too weak to continue on his bike. He took a day off, but the following day, I got another call – this time he was halfway through a minor training ride, but didn’t have the strength to continue and had to turn back. The day after he suffered a terrible headache and felt extremely fatigued – the headache lasted for 3 days – the fatigue lingered on. For an entire week he wanted to get back on his bike, but didn’t have the energy.

It’s easy to overexert in hot weather, and worst of all you may not even notice you have progressed from simply sweating to a more dangerous condition. The end result can be heatstroke, which can be fatal. When it is not fatal, heatstroke can damage internal organs or at the very least leave you nauseated and with a headache you’ll never want to experience again.

Another consequence of over-exertion is exertional, or exercise-induced, rhabdomyolysis (ER), which is a medical condition that results from direct muscle injury or an altered metabolic relationship between energy production and energy consumption in muscle. Causes include drug toxicity, heat stress, muscle trauma and physical exertion. The symptoms are extreme muscle soreness, very dark urine, and generalized malaise, fever, tachycardia, nausea and vomiting, altered mental status (e.g., confusion) and low urine output. Severe cases of ER can be life threatening due to acute renal (kidney) failure.

You can avoid physical overexertion by knowing your body’s limits and listening to your body. In my husband’s case he shouldn’t have attempted to go from 0 miles/day to 100 miles/day in a week. Instead he could have done shorter high impact distances lasting about an hour, which can be equally effective due to a more focused performance. And on the days where the temperature exceeded 100 degrees, it would have been better to decrease intensity and endurance to a minimum, or do his workout in an air-conditioned space. He did complete the Death Ride including all 5 mountain passes – probably not as fast as he would have liked initially, but all considered he was just excited that he was able to finish.