HIIT or miss: How effective is high-intensity interval training?

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In our current fast-paced lives with hectic, packed schedules coupled with long hours and stressful commutes, it's sometimes tough to fit in time for exercise in your day. You may have heard the big fitness trend - HIIT exercise. This type of workout can be as short as 20-30 minutes, meaning you can easily slot it into your daily routine. In this blog, we explain exactly what HIIT means, different types of HIIT workouts and also describe the benefits of this type of training - why is HIIT so effective?

What is HIIT?

High-intensity interval training (HIIT) is a type of aerobic exercise or power training. It focuses on bouts of explosive strength and/or cardiovascular exercise interspersed with periods of rest. To put this into practice, you’d sprint to your maximum capacity for around 30-60 seconds then rest for a couple of minutes. You’d then continue this for about 15 minutes. This example is simply illustrating what a typical HIIT workout could be like – your personal ability and goals will determine the length of your fitness routine. Watch Zanna van Dijk's explosive HIIT workouts on her YouTube channel.

“Going all out” during the HIIT exercises means that they’re usually a lot shorter than regular workouts. The extended recovery periods are necessary for your body to adapt and deal with the physical extremes. This makes HIIT training much more efficient than other types of workout as its easier to fit into your busy day.

What are the benefits of HIIT?

Improve overall fitness and endurance

HIIT exercises tend to improve overall physical performance and athletic ability, being used as an effective training method for cardiovascular workouts. In fact, a fitness study showed that HIIT improved maximum oxygen uptake (VO2max). This is the maximum amount of oxygen that you can use during intense exercise and can be a good indicator of your cardiovascular fitness level.

Heart healthy

HIIT also has important and positive consequences for your heart health! HIIT exercise can improve cardiovascular health – lowering your heart rate and your blood pressure. For adults with high blood pressure, one study found that eight weeks of HIIT on a static bike decreased blood pressure as much as continuous endurance training.

Get your glucose HIIT

Improvements to blood sugar levels have been seen following a HIIT programme. HIIT is shown to help with improving insulin resistance or insulin sensitivity, which helps the body with the transport of sugars in the blood following exercise.

Lose weight faster

Despite the small amount of time dedicated to HIIT exercises, it’s an effective and fast method for fat and weight loss. One study found that doing HIIT three times per week for only 20 minutes each session helped people lose 2kg (4.4lbs) of body fat in just 12 weeks. Although healthy nutrition is important overall, this result didn’t involve any dietary changes. HIIT also lead to a 17% reduction in visceral fat levels, which is the type of abdominal fat that causes dangerous health conditions.

If you’re interested in tracking your health and fitness progress – losing weight, gaining muscle, whatever your goals might be – you can use the Evergreen Life app to record key measurements. Record your weight, body fat percentage, blood pressure, cholesterol levels and more, to see whether your fitness programme is working for you.

Increase your metabolism

As a result of this kind of exercise, your excess post-exercise oxygen consumption (or EPOC) will be much higher, meaning you carry on burning more calories for an extended period of time following your workout. The resulting breakdown of any muscles from the intense exercise will also cause an increase in your metabolic rate for longer after your workout. Basically, you’ll carry on burning calories at a higher rate than normal even when resting.

HIIT: is it in your genes?

You could find out if HIIT is actually the best exercise for you by taking a DNA genetic test. Understanding your genetic makeup can tell you whether HIIT exercise would work for you, helping you to lose weight and burn fat more effectively. Let’s take a look at some of the genes associated with an increased benefit towards doing HIIT workouts.  

Power performance

Also known as NOS3, the eNOS gene makes an enzyme that widens the blood vessels in the body. This process allows more blood flow to the muscles for effective delivery of oxygen. People with the CT or TT genotypes typically have an increased affinity for sports or exercises that require power over endurance. This enhances tissue oxygenation from the blood. Those with this genetic makeup may be more likely to perform better during strength or power activities. They may wish to consider developing their endurance capacity by combining strength exercise with cardiovascular exercise and HIIT.  

More specifically, if you have increased power performance, you could benefit from these types of HIIT exercise:

Glycolytic anaerobic interval training -work for 11-20 seconds; rest time should be triple that of your work time.

ATP-PC (Adenosine Tri-Phosphate Phospho-Creatine) interval training - work for 1-10 seconds, then rest for up to 60 times that amount.

woman running HIIT exercise workout

Fat loss from exercise

The ADRB2 gene plays an important role in muscular, cardiovascular, respiratory, metabolic and hormonal systems. Variations in this gene alter the person’s endurance level and risk for obesity. If genetics indicate reduced fat loss from endurance exercise, then an interval-based approach to cardio could be more beneficial for those with a goal to lose fat. People with this genotype may struggle to burn fat by doing endurance exercise on its own.

Blood sugar regulation

Glucose is an important energy source during exercise. The amount of glucose required rises with the intensity and duration of exercise due to increased muscle activity. If you’re not an effective regulator of your own blood sugar during exercise, you would benefit from breaking up your cardiovascular exercise into manageable intervals with HIIT.

Written by
Evergreen Life

Article updated:
April 9, 2018
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