Exercise Reduces Hidden Fat

Visceral fat, which accumulates in the abdominal cavity, has a greater adverse effect on health than subcutaneous adiposity that shapes our appearance.

With Ian J. Neeland, MD, and Carl J. Lavie, Jr., MD

Every day there are articles about the negative effects of obesity on our health, leading to high morbidity and mortality. Studies have shown that cardiovascular (heart) health and our metabolism are associated less with actual body size (weight and body mass index, or BMI) and more with the type and location of body fat.1

Unlike visible fat stores that collect in front of the abdomen (leading to an apple shape), or that settle on the thigh region (creating a pear shape), visceral fat is a layer of adipose stores that collect deep in the abdominal cavity around our primary organs, including the liver, pancreas, and kidneys.

The presence of this “active” internal fat has a significant impact on hormone production, which, in turn, likely raises a person’s risk of chronic diseases. 

Visceral fat, found around key organs, in the abdomen raises disease risks.

Specifically, we know that visceral adiposity is related to many medical conditions including:1,2

  • metabolic syndrome (MetS)
  • cardiovascular disease (CVD)
  • hyperlipidemia (high blood cholesterol)
  • hypertension (high blood pressure)
  • type 2 diabetes (T2D)
  • some forms of cancer

While there are sound recommendations to manage obesity,3,4 which focus on lifestyle modifications such as diet and physical activity, as well as pharmacotherapies and bariatric surgery,2 to reduce excess body weight—prescribing physical activity to target a reduction in visceral fat—promises to substantially reduce the risks related to many cardiometabolic diseases.  However, there are no current guidelines that identify the most effective means of reducing visceral fat.1

Research Focused on Reversing Adverse Effects of Visceral Fat 

Towards this end, Rao et al conducted a systematic review of the literature to examine the role of exercise compared with pharmacotherapy on visceral fat;2 the findings were published in the Mayo Clinic Proceedings.

 “We wanted to look at long-term changes to assess the effectiveness of exercise versus pharmacotherapy in reducing visceral fat stores,” said lead author Ian J. Neeland, MD, FAHA, assistant professor of medicine and Dedman Family Scholar in Clinical Care in the Division of Cardiology at the University of Texas Southwestern Medical Center in Dallas.

In this study analysis,2 the researchers identified 17 randomized controlled trials (RCTs) that were of longer duration—6 or more months— which collectively involved a total of 3,602 participants.

Any studies that included patients with a medical condition associated with overweight or obesity were excluded so that the results would have better applicability to the general population. The analysis involved 12 exercise trials encompassing 2,094 individuals and six drug trials, involving 1,508 individuals.2 Two of the exercise trials only included patients with diabetes; the remaining exercise trials excluded participants with a diagnosis of diabetes.

There were six drug studies that involved a variety of pharmacologic agents, including gemfibrozil, metformin, rosuvastatin, orlistat, and rimonabant (which was never approved in the US). Additionally, liraglutide and empagliflozin were included in the sensitivity analyses only. Of these drugs, orlistat (Xenical, Alli) at 120 mg TID, was associated with the greatest reduction in visceral fat, with a mean absolute reduction of 67 cm2, followed by rimonabant and gemfibrozil. Both liraglutide, and the combination of empagliflozin and metformin—both common diabetes treatment regimens— demonstrated consistent reductions in visceral fat.1,2

To be included in this analysis,2 the trial had to cite visceral fat levels in test subjects as an outcome measure determined by either via computed tomography (CT) or magnetic resonance imaging (MRI).

Walking can reduce the risks associated with diabetes, heart disease, and other chronic diseases.Most people focus on losing visible fat but the internal fat that accumulates around organs increases disease risk even more. and can be reduced just by exercising a few days a week.

Clinicians Urged to Activity Promote Exercise as a Key Component of Any Treatment Plan

Both exercise and pharmacotherapy achieved statistically significant reductions in visceral adiposity. Exercise interventions were associated with a medium reduction in visceral fat (SMD -0.54) compared to a smaller reduction from any medications (SMD -0.27). However, the mean absolute reduction in visceral fat was greater in pharmacological trials versus those looking at exercise alone (23.9 – 27.8 cm2 vs 15.3 – 40.4 cm2, respectively), owing to the greater overall reduction in visceral fat in control groups,2 according to Dr. Neeland.

As such, the researchers determined that both exercise and drug therapies led to significant reductions in visceral fat with a more substantial reduction in internal adiposity-related to exercise than pharmacotherapy.2

 “Most clinical trials typically look at changes in body weight or body mass index. Assessing these changes alone is a disservice to the patient who, through exercise, might have only lost a few pounds but achieved a substantial reduction in visceral fat,” Dr. Neeland told EndocrineWeb. In fact, lifestyle management programs for weight control and diabetes that feature an exercise component can reduce obesity-related health problems despite little or no weight loss.2

Other studies have shown that exercise is more effective than medications at improving glucose tolerance, reducing blood cholesterol and high blood pressure, and lowering the risk of blood clots.5  In addition to the benefits of weight loss and a reduction in visceral fat, exercise has also been shown to improve emotional wellbeing and sleep.

Clinicians ought to prescribe exercise regularly to patients, and when they do, “exercise recommendations need to be patient-specific, personalized medicine, taking into consideration the patient’s age, capabilities, and other medical conditions, among other factors,” Dr. Neeland said.  

The general recommendation for physical activity in adults is to aim for 150 minutes/week to include moderate-intensity aerobic activity, or 75 minutes a week of vigorous aerobic activity (or a combination of both preferably spread throughout the week),6 according to the Centers for Disease Control and Prevention.  Also, most individuals will benefit from adding moderate- to high-intensity muscle-strengthening activity, such as resistance or weight training, at least twice a week.

An editorial on the study by Ruiz et al,1 they noted that the trials select for this analysis failed to identify the most effective exercise ‘dose’ (ie, frequency, intensity, and volume). Specifically, “no information was provided, however, about the most effective exercise dose (ie, frequency, intensity, and volume). Future dose-response studies are warranted to provide informative data for exercise recommendations,” said Dr. LaVie.

“Although clinicians simply don’t have sufficient time to counsel patients about exercise, we ought to mention the importance of increasing their activity if they aren’t already active, and giving them options such as walking (including hills or an elevated treadmill, to improve balance), swimming, riding a stationary bicycle, or adding a bit of resistance training, on an individualized basis,” said Dr. Neeland.

There is one point on which we call agree Dr. LaVie told EndocrineWeb, “if exercise could ever be taken in the form of a pill, it may be the most universally prescribed medicine.”1

The systematic analysis was supported by a from the National Institutes of Health. None of the cited physicians indicated a financial conflict with regard to this study.

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