September 2019

Sprint Intervals, Body Composition & Menopause

The hormone differences between males and females take a sharp turn at puberty such that females deposit more fat while males add more muscle. At menopause, when estrogen and progesterone levels decline, females lose some of the protections they offer but don’t lose their many years of fat accumulation. In fact, they often develop android or belly fat a la males. As almost any female can attest, this fat is hard to lose without intense calorie restraint and/or significant whole body exercise.

Over the past 15 years or so, interval training, once the purview of track, football, soccer and basketball athletes, has made its mark in mainstream fitness. Generally known as HIIT – high intensity interval training – the combination of short bouts of high intensity cardio with longer recovery bouts is rampant. SIT – sprint interval training – entail very high intensity but brief efforts with longer recovery times comes from the sports world to the fitness and weight management world tenuously. This kind of workout is brutal.

An Australian study divided 40 post-menopausal women into two groups: 8 wks of no change in exercise habits vs 8 wks 3 sessions of SIT (20 mins of 8 sec sprints/12 sec slow recovery) on exercise cycles. DEXA scans – the gold standard – were used pre- and post- to measure body composition changes. Also, aerobic capacity was measured.

Lean mass increased and fat mass decreased in the SIT group, primarily in the trunk and legs. Aerobic capacity also increased (12%.) While the direction of changes was expected, the short time frame and the rate of changes were notable. Clearly SIT is not for everyone. Check with your doctor to see if you’re healthy enough for this kind of workout.                      

MSSE July 2019

HIIT for Brains

What with all the good news for the heart, muscles and body composition about HIIT and SIT, it was only a matter of time before someone investigated its value for the mind. And so, a group out of the University of Queensland in Australia investigated the effects of HIIT on cerebral blood flow (CBF). As we age, especially for those who have cardiovascular diseases like hypertension, hypercholesteremia, or heart failure, or advanced metabolic syndrome (high blood sugar, high body fat/weight especially around the middle, plus high blood pressure and cholesterol), CBF is impaired.

To determine which exercise mode boosts CBF, they studied young (mid-20s) and older (late 60s) males during 10 minutes of intervals (1 min. sprint/1 min slow) on a cycle vs work-matched continuous cycling.

Results demonstrated that HIIT was “as effective as continuous exercise for increasing brain blood flow in older adults during the periods of activity, and more effective than continuous exercise when we measured the overall blood flow increases during both the exercise and the rest periods.”

Because it was a small study that looked at only one bout of exercise, we can’t project what would happen over time. However, most of the research suggests that cardio exercise is good not just for the body but for the mind.                     

MSSE July 2019

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