Everyone knows that exercise is beneficial for health. In many treatment plans for various diseases, exercise is included; in other words, if you want to improve your health, moving your body is the right choice.
However, you occasionally hear some bizarre stories from the gym, like during a bench press, a person might fail to exert enough force, causing the barbell to fall onto their windpipe and lead to suffocation. Or during leg presses, when the knees are locked, the legs might bend in the opposite direction, resulting in dislocated and fractured bones.
In fact, the harm caused by exercise doesn’t just come from using machines. Many things should be done in moderation, and it’s important to know when to stop. Over-exercising can push your body to the limit, leading to poor sleep, frequent colds, and reduced appetite. Besides that, overtraining can also put your body at greater risk. Let’s take a closer look.
◆ Cardiovascular Damage
In our article “Strength Training Safely Without Blood Pressure Spikes,” we mentioned that exercise can cause changes in blood pressure. Usually, aerobic exercise causes a less noticeable increase in blood pressure, ranging from 140 mmHg to 160 mmHg during the workout. But if the exercise is very strenuous, it can reach 180 mmHg to 220 mmHg. Resistance training with heavy weights can cause an even more pronounced increase, frequently pushing the systolic pressure over 300 mmHg.
So, lifting heavy weights can cause sudden and extreme spikes in blood pressure, even up to 300 mmHg. If someone already has risk factors like hypertension or other cardiovascular diseases, it’s crucial to start with aerobic exercise or bodyweight training.
Not only can heavy weightlifting affect cardiovascular health, but overly intense aerobic exercise can too. We know that regular joggers have lower mortality rates compared to non-runners. However, those who engage in intense running more than three times a week have mortality rates similar to non-runners. Running too much or at high intensity can negate the original benefits of exercise.
For example, extreme endurance races like ultramarathons, where participants run 80 kilometers, 100 kilometers, 160 kilometers, or even for 24 hours straight, put immense strain on the cardiovascular system, damaging heart function and affecting heart rhythms and blood vessels. Repeatedly doing this can cause scarring of the heart. One study found that in a group of twelve triathletes, with an average age of 57, who had participated in multiple marathons, ultramarathons, and triathlons, their hearts showed fibrosis and scarring compared to non-exercising individuals of the same age, weakening the heart muscle and increasing the risk of ventricular arrhythmias.
◆ Rhabdomyolysis
Rhabdomyolysis is a condition where the skeletal muscles are directly or indirectly injured. When muscle fibers die, substances inside the muscle cells, such as potassium ions, uric acid, creatine kinase (CK), and myoglobin, are released into the bloodstream. These harmful substances can severely affect kidney function and heart rhythms, leading to a series of problems. Without timely treatment, this condition can be fatal.
Rhabdomyolysis is dangerous and can occur in those who overuse their muscles. It might happen to someone who has had little training but is suddenly asked to do 100 squats by a coach, or as punishment, is forced to do 300 frog jumps. It also commonly affects those who enjoy lifting heavy weights or long-distance runners like marathoners or ultramarathoners. Fitness enthusiasts who take excessive creatine or steroids are also more prone to developing rhabdomyolysis.
When over-exercising leads to extreme muscle fatigue, especially in hot environments or when dehydrated, the individual may complain of severe muscle pain, weakness, and even become unable to move. Their urine turns a dark brown color, resembling soy sauce or cola, and the amount of urine decreases. At this point, immediate medical attention is needed to remove the metabolic waste from muscle breakdown through intravenous fluids, or even emergency dialysis. Without treatment, it can cause kidney failure and be life-threatening.
◆ Stress Fractures
Stress fractures are not caused by a single injury but are the result of repetitive overuse during exercise. Small cracks form in the bones due to repeated stress, leading to pain, muscle weakness, and a tendency for muscle cramps. Stress fractures most commonly occur in weight-bearing bones of the lower body, such as the tibia and metatarsal bones in the feet. Historically, stress fractures were referred to as “march fractures” because they were often seen in soldiers who sustained overuse injuries from long marches while carrying heavy loads.
◆ Immune System Suppression
Regular exercise can boost the immune system, improving white blood cell function and reducing the frequency of colds. However, when exercise is excessive, such as spending long hours at the gym or engaging in very intense workouts, the body becomes extremely fatigued, stress hormone levels increase, and many white blood cells are consumed, leading to suppressed immunity.
Research suggests that even athletes who undergo high-intensity training without sufficient recovery time become more susceptible to colds. Generally, after 1.5 hours of continuous exercise, the immune system begins to decline, and this lowered immunity can last for about 24 hours. Following intense exercise, there might even be a 72-hour window where the immune system is particularly weak, making it easier for viruses and bacteria to take advantage.
（Got a cold? Can you still exercise? Check out these exercise tips (infographic).）
◆ Dehydration and Electrolyte Imbalance
If you feel extremely thirsty during exercise, along with dizziness, fatigue, rapid heartbeat, and muscle cramps, and haven’t urinated for a long time or notice that your urine is dark in color, these are signs of dehydration. Don’t ignore these symptoms—make sure to hydrate and rest. Dehydration not only lowers performance but can also lead to electrolyte imbalances and damage various organs.
Many fitness enthusiasts, especially those preparing for physique or bodybuilding competitions, manipulate their weight through extreme methods like bulking diets, fasting, or dehydration. This frequent fluctuation in weight can strain the heart, kidneys, and liver.
◆ Heat Exhaustion
Some people like to train in hot environments, believing it can improve cardiovascular fitness, speed up metabolism, and help with weight control. However, exercising in hot conditions causes body temperature to rise with the environment and effort, potentially leading to heat exhaustion.
Individuals suffering from heat exhaustion can experience body temperatures as high as 39°C or 40°C, or even higher, along with confusion, nausea, vomiting, fatigue, dizziness, and weakness, eventually leading to seizures and unconsciousness.
Therefore, it’s important to choose a safe environment for exercise and avoid high temperatures. For outdoor activities, use sun protection, wear light and breathable clothing, and stay hydrated with water and electrolytes.
Finding Balance
Whether exercise leads to health benefits depends on factors such as age, health status, and choice of fitness activities. Current recommendations for adults suggest at least five days a week of 30-minute aerobic exercise, combined with strength training twice a week. You can create a plan based on this, choosing activities like brisk walking, jogging, swimming, cycling, or hiking for at least 30 minutes five days a week, and adding strength training to build muscle mass and strength.
However, if you feel your workout is making life unbearable, it’s time to adjust and find an exercise routine that suits you. Avoid overtraining or engaging in high-intensity workouts for extended periods. When choosing higher intensity, shorten the duration of the workout accordingly.
