In the 1960s, a man name Kenneth H. Cooper came up with the concept of aerobics. Originally,
aerobics, via the aerobics point system, measured the effectiveness of different exercises and
activities for improving cardiovascular health. This lead to the coining of the term today
known as cardio. Over time, however, the main focus of these aerobic-based exercises began
shifting from improving cardiovascular health to helping people lose weight and burn fat.
And it makes a lot sense since cardio exercises do indeed help people lose weight by burning
excess calories and also help people burn fat by activating the fat-burning aerobic
energy pathway in the body. This aerobic energy pathway is the energy
system in your body that uses stored fat- after being converted into fatty acids- in
conjunction with oxygen and other chemicals to produce the body's sole source of energy
known as ATP. As long as this pathway is utilized, more and more fat will be burned. Early science
believed that the best way to activate this pathway is by performing long-duration, low
intensity exercises such as long-distance jogging, cycling, or swimming. This ultimately
lead to the creation of other forms of cardio exercises today such as aerobic dance classes,
step aerobics, and the extremely popular Zumba. Although low intensity cardio is still the
exercise king of weight loss and fat burning today, newcomers have arrived to challenge
for the crown. The biggest gripe with low intensity cardio exercises is the duration,
which often takes more than an hour. Cardio might seem to be fun and exciting the first
time it's done, but over time, it begins to feel way too repetitive and long. As more
and more people become bored and lose interest, more and more people will quit. And for some
people, they simply do not have the time. But are low intensity cardio exercises really
the best option to burn fat and calories? The science today says, "Ehh, probably not."
This is where the most prominent challenger to low intensity cardio steps in. This challenger
is known as High Intensity Interval Training. High Intensity Interval Training, as the name
suggests, is any "training" program that are performed in "intervals" at a "high intensity."
High intensity interval training, also called HIIT for short, are alternating periods of
short high intensity activity with periods of low intensity recovery. The most popular
exercise for HIIT is alternating sprinting with walking. Each sprint interval lasts between
5-30 seconds and each walk interval will also last between 5-30 seconds. The more fit you
are, the higher the work to rest ratio will become. For example, if you're really fit,
you might be sprinting for 30 seconds and walking for 10. Someone that is less fit might
be sprinting for 10 seconds and walking for 30. The total session length varies between
5-20 minutes, and because of the intensity, should only be done 3 days a week. When added
together, that's a maximum of only 60 minutes of exercise per week!
So what's the science behind this? When the body goes through intense activity, it needs
to be able to keep up with the energy demand. One way of doing so is by secreting high levels
of fat-releasing hormones known as catecholamines into the bloodstream. The more catecholamines,
the more quickly fat is broken down into free fatty acids. Free fatty acids are then used
to replenish energy stores. Studies have also shown that HIIT creates a strong EPOC effect.
EPOC, short for excess post-exercise oxygen consumption, is the extra oxygen your body
needs in order to recover after an intense activity. The more oxygen you take in also
means more calories are being burned. This effect can last up to an amazing 24 hours
after the workout. However, other studies have shown that the amount of calories being
burned during EPOC isn't all that much, where at most an extra 60 calories being burned.
There are also a few drawbacks. High intensity interval training is extremely strenuous.
People might drop out of low intensity cardio becomes it's long and boring, but people can
just as easily drop out of HIIT because it's just too hard. High intensity interval training
might also cause joint pain due to the high impact, and over time, might lead to serious
injuries. Also, low intensity cardio can actually be done every day. HIIT, however, requires
ample recovery time, which can interfere other exercise routines. Although HIIT might challenge
low intensity cardio for the crown, it's not exactly a knockout punch.
Have you tried high intensity interval training before? Please share your experience in the comment section below!