In recent years, there’s been a big push toward using high intensity interval training—or HIIT as it’s called for short—to reach higher levels of fitness even though the exercise sessions are much shorter than traditional recommendations. Further, one of the main arguments used for adding HIIT to a person’s exercise routine is that this particular form of exercise can be more beneficial to one’s fitness than continuous, moderate-intensity exercise.
The real question is: Does research actually support this claim? Is HIIT really as beneficial as fitness experts would like us to believe? In order to answer this, you must first understand VO2 max.
VO2 Max, HIIT, and Fitness
Sport Fitness Advisor explains that VO2 max is essentially the maximum amount of oxygen your body consumes while engaged in high-intensity exercise. The reason this number is important is because “it is generally considered the best indicator of cardiorespiratory endurance and aerobic fitness,” according to Sport Fitness. In other words, the better (higher) your VO2 max, the more fit you are.
Many studies have been conducted around HIIT and how it affects your VO2 max, ultimately giving researchers an idea of how this type of exercise compares to others in improving one’s fitness levels. The findings? Quite a few have noted some promising results.
For example, a 2015 meta-analysis published in the journal Sports Medicine looked at 28 different studies which measured VO2 max of a total of 723 healthy 18-45 year olds who engaged in HIIT for two weeks or more. After completion of the studies, researchers noted “a possibly small beneficial effect” for those who participated in HIIT training.
They further noted that this positive effect was even greater if HIIT repetitions were longer, the person had a lower fitness level at the start, and there was a greater work-to-rest ratio. That’s 28 studies that support the notion that HIIT can help improve one’s fitness.
HIIT Benefits and Gender
Apparently, there are HIIT benefits based on gender as well. For instance, one 2013 study published by the Journal of Strength and Conditioning Research involved eight men and eight women who were all asked to complete three treadmill-based HIIT sessions. Each session consisted of six 4-minute high-intensity intervals separated by recovery periods that ranged from one to four minutes each.
After reviewing the findings, researchers discovered that, while this form of exercise was efficient for both sexes, the female participants tended to “self-select intensities resulting in greater cardiovascular strain,” ultimately improving their recovery based on the amount of oxygen they consume.
HIIT Also Offers Health Benefits
Not only has research shown that HIIT-style workouts tend to offer participants a VO2 fitness advantage, but it’s also linked HIIT to other health benefits as well. One such study was published in Obesity Reviews in late 2015, sharing how HIIT helps improve fasting glucose levels in individuals who either have or are at risk of having type 2 diabetes.
Another study, this one in the Journal of Strength and Conditioning Research, found that HIIT helps improve high-density lipoprotein cholesterol (HDL) levels, ultimately “eliciting favourable changes” in this number. This is important since HDL is your “good cholesterol” and ultimately responsible for helping to remove “bad cholesterol” or LDL from your blood stream according to WebMD.
How to Incorporate HIIT In Your Training Regimen
Because of scientifically-verified benefits of HIIT such as these, it may be helpful to add this type of training to your current exercise regimen. One way to do this is to join a gym or recreational centre that offers HIIT training classes, allowing you to complete your high-intensity interval workout with others who can help support you along the way.
All in all, research does tend to support the benefits of HIIT—both in fitness and in health. That may make it one worth trying if you’re looking for a new workout regimen that appears to offer many promising results.