Hi. Have you ever wondered how much is too much exercising? We know that fitness level is a function of how often we exercise, how long we do it and at what intensity level we workout. You may have often come across the banal ‘thrice a week for 30 minutes’ phrase. There is research-backed reason for this lower limit. However, there are upper limit cautions as well.
As per the ACSM (American College of Sports Medicine), each session should ideally last from 20 to 60 minutes (duartion) and should be performed 3 – 5 days a week (frequency) at a an intensity level measured by heart rate (60%-90%).
In the first 15 minutes of aerobic activity, glycogen within the muscles is used to provide energy for the workout. Fat metabolism for energy does not begin about 15-20 minutes after the exercise has begun. Taking a margin for level of intensity of your workout and your weight and body type, lower bar has been set to 30 minutes minimum for workouts.
Aerobic activities longer than an hour also contribute to burning fat. However, the rate of burning fat reduces after the first one hour. Also, the chances of injury caused by fatigue increases exponentially beyond the 1-hr mark. Aerobic activity more than 5 times a week is also risky for similar reasons besides it not getting adequate rest facilitating recovery to tissue and muscles. Listen to your body signals, rest, sleep and eat well in the non-workout days.