When it comes to exercise, people usually subscribe to the notion that “more is better.” Many health organizations recommend at least two hours of moderate exercise a week, claiming that ramping up to five hours or more confers even more health benefits.
What if the key to getting the most out of exercise wasn’t the amount, but the intensity? What if you could get as many (if not more) benefits from as little as a couple minutes of exercise a week as opposed to several hours?
It may sound like I’m a television fitness guru that’s trying to sell you a series of DVDs, but I’m not. What I’m talking about is high-intensity interval training or HIIT. The time commitment is low and the benefits are real.The time commitment is low and the benefits are real for high-intensity interval training (HIIT) Click To Tweet
How do HIIT and traditional exercise differ?
Exercises such as jogging, walking or cycling are usually given shorthand names like steady-state cardio or aerobic exercise. Their key features are that the intensity is low to moderate and the time commitment is usually 30 minutes or more a session.
In contrast, HIIT is characterized by extremely short periods of all-out intensity (such as sprinting) followed by timed rest periods. Watch this clip from an episode of BBC’s Horizons series. It shows how short, but intense HIIT can be:
Why you may want to cut back on long-term steady-state cardio
Doing things like going for a short, daily walk or participating in a yoga class is great for your health. Research reviews continually show that regular physical activity is helpful in managing and preventing chronic diseases like diabetes and high blood pressure.
However, when people commit large portions of time to steady-state cardio activities (think Iron Man participants and endurance athletes), the health benefits start to taper off and negatives can be the unfortunate result.While lots of cardio may seem healthy, consistently overdoing it may result in negative health effects Click To Tweet
Studies from the Mayo Clinic, Journal of Applied Physiology, Medicine and Science in Sports and Exercise and the European Heart Journal have found endurance athletes show abnormal thickening of heart valves, a potential sign of heart failure.
That same population has been found to have highly-elevated levels of cortisol (a stress-response hormone), increased C-reactive protein (a sign of inflammation) and exhibit symptoms like immune system deficits, sleep difficulties and mood disturbances.
What are the benefits of HIIT?
Whereas too much long-term steady-state cardio can have negative effects on an individual’s heart, low volumes of HIIT (around three sessions a week) can improve heart artery stiffness and cardiovascular functions.
Studies have shown HIIT to have many other benefits such as:
- Improved HDL or “good” cholesterol
- Increased insulin sensitivity
- Reduced blood pressure and better glucose tolerance
- Increased ability to build muscle
- Greater mitochondria creation
- Metabolic adaptations that reduce the risk for inactivity-related disorders
How do you perform a HIIT session?
Some online guides complicate HIIT, calling for things like mixing free weights with bodyweight squats. An effective HIIT session really can be as simple as the video clip above from BBC Horizons.
If you’re just starting and/or want to keep things simple, stick with one form of cardio, such as sprinting or cycling on a stationary bike. Then follow a template such as this up to three times a week: