Survey ten people at any gym and ask them what they hope to gain from exercise and most probably answer with, “A slimmer waist and six-pack abs.” However, data from one of the largest health studies ever provides us with a great deal more motivation then simply looking good in a swimsuit. Tobias Pischon, MD, lead author of the report, explains it this way, “Our study shows that accumulating excess fat around your middle can put your health at risk even if your weight is normal.”
Health conditions we associate with excess fat are premature death, high blood pressure, heart disease, Type 2 diabetes, dementia and even some types of cancer.
Big Waist = Big Trouble
Pischon found, “The distribution of body fat, affects the risk of premature death." Specifically, those with the largest waists (greater than 35 inches for women and 40 inches for men) had two times the risk of premature death versus those with the smallest waists (less than 28 inches for women and 34 inches for men). The table below stratifies your risk. Keep in mind that waist size is independent of weight, body mass index, and even height. This means storing fat at your waist is a serious risk factor no matter what shape or size you are.
Risk Category / Women / Men
Very Low / 28.5 inches / 31.5 inches
Low / 28.6 - 35 inches / 31.6 - 39 inches
High / 35.6 - 43 inches / 39.5 - 47.0 inches
Very High / Greater than 43 inches / Greater than 47 inches
Types of Fat
Your body stores fat in two areas - in the subcutaneous or visceral. Subcutaneous fat is the type most of us worry about and is found under our skin. It’s what we can see and pinch. Health care professionals worry about visceral fat. This is the fat deep in the body that surrounds the internal organs. Kristen Hairston, MD (an assistant professor of endocrinology at Wake Forest School of Medicine) describes its effect on our health this way… “it secretes lots of nasty substances.” These substances increase inflammation in the body and lead to diseases like cancer, diabetes, and hypertension.
Exercise That Targets Your Waistline
Research shows us that High Intensity Interval Training (HIIT) is not only one of the best ways to lose weight, but it’s also very effective at targeting fat around your waist. Stephen H. Boutcher, PhD (an associate professor at the University of South Wales) and his associates examined the impact of 12 weeks of HIIT training on body composition on overweight males. Forty-six inactive, overweight men volunteered to participate and were randomly assigned to either a control group (no exercise) or the exercise group. The researchers instructed both the control group and exercise group to maintain their normal eating habits during the study. Exercise subjects then completed three weekly exercise sessions over twelve weeks consisting of thirty minutes of stationary cycling. Subjects performed a five-minute warm up and cool down. The majority of their exercise time (20 minutes) was spent performing intermittent high intensity exercise consisting of eight-second sprints followed by 12 seconds of active recovery.
At the end of the study, Boutcher compared the two groups. The exercise group participants’ total fat loss was over four pounds. More importantly, the majority of the fat lost came from the abdomen and trunk. Exercise group subjects decreased their waist size over one inch from 36.7 to 35.4 inches, while control group subjects gained almost an inch with an increase from 36.7 to 37.4 inches over the same time period.
Fat Loss Mechanisms
When asked about HIIT’s effectiveness, Boutcher responded that, “It significantly elevates a hormone called catecholamine and these are important messengers to tell the cells to burn fat”. Furthermore, fat cells around the waist contain more catecholamine receptors than those in other areas of the body. Because of this, the body uses more of them to fuel exercise. However, HIIT training also triggers the release of both cortisol and growth hormone. Cortisol is a powerful steroid hormone responsible for increasing fat metabolism, ensuring adequate fuel through gluconeogenesis, and catabolizing protein for amino acids to repair muscles and synthesize enzymes. Growth hormone on the other hand is an anabolic agent that increases fat metabolism and promotes the transport of amino acids, which increases protein synthesis.
Finally, the intense nature of HIIT sessions causes your body to spend a great deal of time and energy to remove lactate (a common exercise by-product), reduce hydrogen ions (generated from reducing ATP to fuel exercise) and to re-build your glycogen stores--all of which increase caloric expenditure. While steady state exercise increases metabolism, it does not cause the large spike in hormones seen with HIIT, which explains why it isn’t as effective.
Routines That Reduce Waist Size
Boutcher’s protocol couples eight-second sprints with twelve seconds of active rest over twenty minutes. This routine consistently results in fat loss at the waist. He credits its success to, “trial and error and prior research…we’ve established what seems optimal for most people.” Boutcher’s heart rate goal for subjects during sprints is 80-90% of their heart rate peak achieved during a fitness test. Throughout training, he adjusts the workloads as fitness improves.
To determine your heart rate goal and workload, you first need to figure out your VO2 max. This isn’t as hard as it sounds as most cardio equipment in gyms has a fitness test program. The numbers to record are your VO2 max in ml/kg/min along with your maximum heart rate. These numbers are important so you don’t under or overestimate how hard your fitness level. Use both of these pieces of information to plan your workout.
Fitness Test Results
VO2 Max = 48 ml/kg/min
Maximum MET level achieved = 48/3.5 = 13.71 METs
Maximum heart rate achieved = 180 bpm
Workload Ranges
80-90% of max heart rate = 144-171 bpm
80-90% of max METs = 11-12 METs
HIIT Workout
Warm-up: 5 minutes of pedaling at a comfortable pace
Workout: 20 minutes
8-Second Sprint
Cadence: 120-130 revolutions per minute
Heart Rate Goal: 144-171
Workload in METs: 11-12 METS
12 Seconds Active Rest
Cadence: 40 revolutions per minute
Cool-Down: 5 minutes of pedaling at a comfortable pace
Lower extremity stretching
While most HIIT studies use stationary bikes Boutcher feels, “the rower and cross trainer are probably equally effective and so is skipping.” But he also says that, “walking won’t get your heart rate up high enough."
Conclusion
If you eat clean and hit the gym on a regular basis, and the tape measure still doesn’t move it’s time to try something new. Replace two steady state exercise sessions a week with HIIT. Jump on the elliptical trainer at the gym, and thirty minutes later you’re done with a great workout. Over time, subcutaneous and visceral abdominal fat levels will decrease. You’ll look better, feel better and be a whole lot healthier.
If you try this routine and want to share your success or need some more information, let us know by posting in the article discussion thread or on our Facebook page.
References
1. http://www.webmd.com/diet/news/20081112/belly-fat-doubles-death-risk
2. http://www.webmd.com/diet/features/the-truth-about-belly-fat
3. M. Heydari, J. Freund, and S. H. Boutcher, “The Effect of High-Intensity Intermittent Exercise on Body Composition of Overweight Young Males,” Journal of Obesity, vol. 2012, Article ID 480467
4. http://health.ninemsn.com.au/whatsgoodforyou/theshow/694660/a-weight-loss-revolution
5. Boutcher S.H., “High Intensity Exercise and Fat Loss”, Journal of Obesity, vol. 2011, Article ID 868305
6. http://newsroom.unsw.edu.au/news/health/sprint-fight-fat.
7. E.G. Trapp, D.J. Chisholm, J. Freund, and S.H. Boutcher. “The Effects of High Intensity Intermittent Exercise Training on Fat Loss and Fasting Insulin Levels of Young Women.” International Journal of Obesity. 32: 684-691, 2008.
Mark Kaelin – Mark is an instructor in the biology department at Bellarmine University. He has a Master of Science in exercise physiology from the University of Louisville and is a certified strength-and-conditioning specialist with the National Strength and Conditioning Association. Mark has been writing since 2001, with work appearing in both consumer and research journals.