It is possible to do too much cardio. What counts as "too much" is different for everyone, and depends on a lot of factors, including the intensity of your exercise, your fitness level, how much activity you do each day, how much you eat, your health status, your fitness goals, etc.
Usually, 60-90 minutes of cardio is safe for most people, as long as…
You aren't elevating your heart rate above 80% (of your max) the whole time
You are eating enough carbohydrates every day to replace the fuel you are using up.
Your body perceives exercise as a stressor, and chemically reacts the same way it does to "bad" stress. Therefore, too much exercise can have negative effects on your metabolism the same way that eating too few calories can. In addition, too much cardio exercise can result in muscle loss, which is not the outcome you want.
SparkPeople's experts recommend taking at least one day off from the cardio during the week—just as a mental health day, if nothing else. It's easy to become compulsive about exercise, and having a day off is a good way to stay away from that. If it really makes you nervous or uncomfortable NOT to exercise, you could be heading for trouble.
If you see signs of general fatigue, irritability, sleep problems, physical soreness, or if your workouts start feeling harder than before, you'll probably need to rest from cardio more than one day.
SparkPeople, SparkCoach, SparkPages, SparkPoints, SparkTeams, SparkDiet, SparkAmerica, SparkRecipes, DailySpark, and other marks are trademarks of SparkPeople, Inc. All Rights Reserved.
SPARKPEOPLE is a registered trademark of SparkPeople, Inc. in the United States, European Union, Canada, and Australia. All rights reserved.