What if I told you could be healthier, live longer and perform better for the rest of your life, but there was a catch… (There’s always a catch!)
The catch is, you would have to spend 5 hours every week at the gym. You still in?
It is well established that people who indulge in 3–5 hours of continuous moderate-intensity exercise per week maintain a higher physical fitness level and have a reduced risk of developing metabolic and cardiovascular diseases. However a lot of people are not able to adhere to this protocol due to time constraints (work, spouses, Game of Thrones marathons).
A recent research by Shepherd et al. (2013) published in the Journal of Physiology provides a solution for those of you with time commitment issues. (Yes! More Game of Thrones marathons!)
Insulin resistance is one of the core factors responsible for obesity and type-2 diabetes. High intramuscular triglyceride (IMTG) concentrations are also known to be a contributing factor. Endurance training helps to increase the oxidation and utilization of IMGT and prevents accumulation of metabolites of IMTG, thus blunting insulin resistance. High Intensity Interval Training (HIIT) is also known to improve aerobic capacity and insulin sensitivity and requires a lower time commitment than ET.
This study aimed to determine whether HIIT also induces improvements in insulin sensitivity and net IMTG breakdown, similar to ET. The researchers studied expression of two proteins – PLIN2 and PLIN5 – as markers, since they believed them to be key regulators of intra-muscular lipolysis and triglyceride breakdown.
They designed a six-week experiment in the course of which 16 previously sedentary young men (BMI ~23kg/m²; age 21.5y) were assigned randomly to one of the following groups:
The results showed the usage of intramuscular triglycerides (IMTGs) during exercise was increased after both trials. Pre and post training, the IMTG content of Type 1 muscle fibers was decreased with HIIT (pre-training, 21±13%; post-training, 38±7%) and ET (pre-training, 20±17%; post-training, 32±8). This adaptation may be mediated by an up-regulation of PLIN2 and PLIN5 proteins known to be involved in regulating IMTG breakdown.
Researchers said "Despite the large differences in duration and energy expenditure between HIIT and ET, we provide novel evidence indicating that HIIT induces similar improvements [in almost all measured parameters and] provides a time-efﬁcient exercise alternative to achieve improvements in aerobic ﬁtness and insulin sensitivity."
So, now it's up to you. HIIT (More spouse time!) 3x per week or ET 5x per week? If you don’t have time to commit to a weeklong exercise routine, then opt for a shorter schedule of HIIT. This will help you to be more compliant towards exercise and also achieve your health and fitness goals. The goal, after all, is to perform better at life.