How Many Sit-ups Should You Do A Day To Lose Weight?

The American College of Sports Medicine recommends a weekly routine of cardiorespiratory, strength and flexibility exercises. Sit-ups can be among the 8 to 10 strength exercises that the ACSM urges people to do. The ACSM recommends 8 to 12 repetitions of each of these exercises two to three times weekly. Making sit-ups one of the strength exercises means doing 16 to 36 sit-ups weekly, but you can do a lot more if improving your abdominal muscle strength is a primary goal.

Recommendations

The ACSM's recommendations about strength, or resistance, exercises are in its 1998 report, "The Recommended Quantity and Quality of Exercise for Developing and Maintaining Cardiorespiratory and Muscular Fitness, and Flexibility in Healthy Adults." Each strength exercise should improve a specific muscle's strength. Sit-ups per minute are the best way to measure abdominal strength, according to the National Institutes of Health. The ACSM also recommends 20 to 60 minutes of cardiorespiratory exercises such as bicycling and swimming three to five days weekly and stretching each major muscle group for about 90 seconds two to three days weekly.

Sit-ups Per Minute

The ACSM estimates that a strength-exercise routine with its recommendations takes 20 minutes. Consequently, 10 repetitions of each of the 10 strength exercises that you do takes about two minutes each. The ACSM's five-repetitions-per-minute calculation seems low, but it includes a short rest between each exercise. You should be able to do five sit-ups per minute for two minutes and 100 sit-ups over 20 minutes, including rest, if you focus on strengthening your stomach rather than all your muscles.

Burning Calories

You can do thousands of sit-ups and gain weight if you eat a lot of calories. What's crucial is calculating weight loss via sit-ups alone. Doing sit-ups for one hour with a "vigorous effort" burns 690 calories if you weigh 190 lbs., 563 calories if you're 155 lbs. and 472 calories if you're 130 lbs., according to Wisconsin's "Calories Burned Per Hour" chart. The ACSM notes that you're exercising vigorously if your heart rate is 70 to 90 percent of your maximum heart rate, or 220 heartbeats per minute minus your age. Doing sit-ups for one hour with a moderate effort, which is 55 to 69 percent of your maximum heart rate, burns 388, 317 and 266 calories if you weigh 190, 155 and 130 lbs., respectively.

Losing 1 lb.

You lose 1 lb. when you burn 3,500 calories more than you eat. You could lose 1 lb. per week or 500 calories daily if you added sit-ups to your daily exercise routine over the course of a week. People who weigh 155 lbs. and burn 563 calories per hour doing sit-ups vigorously need to do sit-ups for about 53 minutes daily to lose 500 calories daily. They will do 265 sit-ups during those 53 minutes if the ACSM's 5 sit-ups per minute estimate is correct. You can also lose 1 lb. per week doing 265 repetitions of other calisthenics, including push-ups and pull-ups.