Health Myths Debunked: Do You Need To Exercise 20 Minutes Consecutively For Any Benefit?

by | Sep 22, 2016 | Last updated Feb 15, 2022

A few weeks ago you asked: “Does eating 6 small meals a day speed up your metabolism?

This week we’re taking on the infamous: Do You Need To Exercise 20 Minutes Consecutively For Any Benefit?

The Myth

You need to exercise 20 minutes consecutively for any benefit.

The Background

As you begin exercising, carbohydrates are your body’s main source of fuel. After about 15-20 minutes of continuous light to moderate intensity activity (think brisk walking, light jogging, or leisurely swimming), fat becomes your body’s main fuel source. This is how the idea that the body only starts to burn fat (or benefit) from activity after about 20 minutes was born.

The Facts

In reality, your body is constantly burning energy in the form of glucose and glycogen (circulating and stored carbohydrates, respectively), as well as fat, not just when you’re active! Even as you’re sitting down reading this article you’re burning calories, and just over half the energy you burn at rest is actually from your fat stores. As you begin physical activity, your body relies primarily on carbohydrates for energy. As you continue moving, your body switches to use primarily fat for energy, since you have a lot more fat reserves. However, your body is never exclusively burning carbohydrates or fat. And regardless of what is being used as fuel, you are burning calories, which is the most important part of creating the calorie deficit you need to achieve weight loss.

Study after study has shown that there are major benefits to physical activity, no matter how short the interval — yes even under 10 minutes!. Research has shown that the greatest improvements in health are achieved by going from being inactive to doing some form of regular activity, with less drastic improvements occurring when active people even further increase their activity level. Going from no activity to some activity can help you improve your overall health and well-being and reduce your risk of chronic conditions, such as diabetes and cardiovascular disease!

Research has also suggested that the benefits of small bouts of intense activity are just as good (or even better!) than longer bouts of less intense activity. Studies have found that high intensity interval training or HIIT (short intervals of “all out” exertion followed by bouts of low-intensity recovery) can help burn more calories, improve your physical fitness, and reduce your fat (including visceral fat, which is associated risk of chronic conditions) in half the time when compared to steady state activities (keeping a pace on a bike or treadmill).

The Bottom Line

While it’s recommended that you get at least 150 minutes of moderate intense activity (like brisk walking) or 75 minutes of vigorous activity (like HIIT style workouts) each week, any activity is better than no activity and can benefit all aspects of your life!

Don’t let a time crunch prevent you from getting moving — you can break down 30 minutes of activity per day into 3 shorter workouts without missing out on any benefits. Or, try switching up your longer, lower intensity workouts with shorter, more intense activity to suit your busy lifestyle and help you reach your goals.

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