Is a 4 hour workout too long?
Workouts should last no less than 60 minutes and no more than 90 minutes. This is sufficient time to challenge your body with quality reps. Anything more, and you'll see diminished returns for your efforts. If you feel inclined to train longer, it's best to split up your workout.
Too much exercise can cause the body to store fat. It's tempting to do as much exercise as possible to lose weight. However, working out three or more hours a day may change your body's response to your exercise routine, making it store fat instead of burning it for energy.
While exercise has more plusses than a math workbook, you can take it too far: If you burn more than 6,500 calories a week with exercise (that's roughly 13 hours) or if you do more than two hours in a row of straight cardiovascular training.
Time at the Gym Per Week: 3 to 4.5 hours
But don't bank on settling into just one routine if you want to improve endurance. "The body will adapt and need to be challenged by a more rigorous routine.
- Being unable to perform at the same level.
- Needing longer periods of rest.
- Feeling tired.
- Being depressed.
- Having mood swings or irritability.
- Having trouble sleeping.
- Feeling sore muscles or heavy limbs.
- Getting overuse injuries.
Compulsive Exercising
Compulsive exercise, according to the NIH, is when exercise no longer feels like an activity you choose to do, but becomes an activity you feel you have to do (or it becomes addictive).
If your goal is to improve your health and reduce your risk of a range of conditions from diabetes to heart disease to cancer, then 2.5 to 3 hours of moderate to vigorous exercise per week gets you the vast majority of benefits, Dr. Levine said.
“Workouts should be no more than 90 minutes,” Makwana advises. “Ideally, 60 to 90 minutes is okay if you're a busy professional. The goal should be to get in and out rather than spending two to three hours, which is not going to be productive for anyone in general, especially if you are busy.”
If you're training six or seven times per week but you're not training for a specific sport, event or competition, chances are you're overtraining.
“Overtraining can lead to overuse injuries such as muscle strains, stress fractures or tendon injuries.” Plus, when you exercise too much, you may lose your motivation or simply no longer enjoy your sports or workouts,” said Amy Jo Overlin, MD, a sports medicine physician at Banner Health in Phoenix, AZ.
How is over exercising harmful?
Exercising too much without resting enough in between can lead to low testosterone levels and high levels of cortisol, the stress hormone. These hormonal changes are often associated with loss of muscle tissue, weight gain, and excess belly fat.
In fact, it's possible that training for five to six hours a day could be doing more harm than good (more on that in a bit). Additionally, you also raised concern about muscle catabolism, which occurs when your body breaks down muscle for fuel.

If spending hours at the gym isn't your thing, take heart. Recent studies report that shorter bouts of exercise at a higher intensity can improve fitness more than working out at a moderate pace for longer periods of time.
You should cap your cardio at no more than 3-4 sessions a week and no longer than 20-25 minutes per session, no matter the intensity.
As a general goal, aim for at least 30 minutes of moderate physical activity every day. If you want to lose weight, maintain weight loss or meet specific fitness goals, you may need to exercise more. Reducing sitting time is important, too.
- Symptom 1. You're feeling tired, strung out, and crabby. What your body is trying to tell you: It may be maxed out. ...
- Symptom 2. You're sick — again. ...
- Symptom 3. You've hit a plateau and you can't seem to climb any higher. ...
- Symptom 4. Your workouts aren't bringing you joy.
The telltale sign of overtraining is a lack of improved performance, despite an increase in training intensity or volume. Decreased agility, strength and endurance, such as slower reaction timesand reduced running speeds are all common signs of overtraining.
A new exercise regimen puts stress on your muscle fibers. This causes small micro tears, also known as micro trauma, and some inflammation. Those two conditions in your muscle fibers are the reason you may gain some weight.
In fact, it's possible that training for five to six hours a day could be doing more harm than good (more on that in a bit). Additionally, you also raised concern about muscle catabolism, which occurs when your body breaks down muscle for fuel.
To reap the health benefits of regular exercise, the AHA suggests that adults gradually increase the amount and intensity of exercise to reach a goal of 300 minutes (5 hours) of physical activity per week.
Is 3 hours of exercise too much?
If your goal is to improve your health and reduce your risk of a range of conditions from diabetes to heart disease to cancer, then 2.5 to 3 hours of moderate to vigorous exercise per week gets you the vast majority of benefits, Dr. Levine said.
When you workout for that long you will actually cause more harm than good, hurt your joints, and cause muscle wasting instead of muscle building. If you are lifting it should be no longer than an hour for a session, otherwise you aren't being efficient during your workouts.
Weight gain
Exercising too much without resting enough in between can lead to low testosterone levels and high levels of cortisol, the stress hormone. These hormonal changes are often associated with loss of muscle tissue, weight gain, and excess belly fat.
You should cap your cardio at no more than 3-4 sessions a week and no longer than 20-25 minutes per session, no matter the intensity.