You might love the feeling of an invigorating cardio workout, but the frequency, intensity and duration of your workouts are important factors to consider. Too much cardio can result in muscle loss, heart damage, depression and anxiety. But don't worry – you can avoid cardio overload by diversifying your workout and remembering to rest.
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Too Much Cardio Can Be Bad for Your Health
The consequences of too much cardio can be bad: Some endurance athletes who overtrain in cardio exercises like running can experience many of the negative health effects of those who don't exercise at all, according to U.S. News & World Report. For instance, they can suffer hardening of the heart muscles and an increased risk of cardiac arrest. Studies showed that individuals who ran more than 25 miles a week had a mortality rate similar to those who did no exercise at all.
If you're experiencing any of the signs of overtraining – prolonged feelings of exhaustion soreness, depression, anxiety and insomnia, for example – review your fitness routine with your doctor.
Read more: Signs & Symptoms of Overtraining
Rest Days Are Important to Cardio Training
Though it may seem counterintuitive, one of the best things you can add to your daily routine is the occasional day off. When you exercise, some of the individual fibers in your muscles, called myofibrils, tear. That soreness needs a day or two to heal properly, allowing you to build muscle over time. Doing the same amount of cardio every day can inhibit your recovery, causing you to lose muscle over time.
Active Recovery and Cardio Workouts
If you just can't stomach the idea of going a day without cardio exercise, a very mild cardio workout, done once or twice a week, can substitute for a rest day. These "active recovery" days should include low-intensity exercises done for shorter durations than those included in your normal workout. Stimulating your muscles through moderate exercise works to rebalance your hormones and help your muscles recover faster.
Read more: Refuel - A STRONGER Active Recovery Workout
Cardio in Moderation
The U.S. Centers for Disease Control and Prevention recommends about 150 minutes of moderate cardio exercise per week, but it notes that high-intensity exercise of a shorter duration makes a good substitute. The CDC describes moderate cardio exercise as that which raises your heart rate and causes you to break a sweat, such as brisk walking, water aerobics, cycling on level ground or light hills, playing doubles tennis and cutting grass with a lawn mower.
High-intensity cardio that gets you breathing fast and your heart pumping hard may include jogging or running, swimming laps, cycling fast or on hills, playing singles tennis and playing basketball.
For the best results, diversify your cardio workout with high-intensity exercise and rest or active recovery days when you need them. "A rule of thumb is that 1 minute of vigorous-intensity activity is about the same as 2 minutes of moderate-intensity activity," the CDC says.