Vigorous Exercise Versus Moderate Exercise to Improve Glucose Metabolism and Metabolic Parameters in Women With Polycystic Ovary Syndrome and Insulin Resistance: A Prospective Randomized Pilot Study

Polycystic ovary syndrome (PCOS) is a common endocrine disorder with an incidence of 5-8% in reproductive aged women. PCOS is characterized by a collection of signs and symptoms, and as defined by the 2003 Rotterdam criteria must include two out of the following three characteristics: oligo-ovulation or anovulation, polycystic-appearing ovaries, and clinical or biochemical evidence of elevated androgens.

Women with PCOS are also known to have an increased risk of metabolic disorders, including insulin resistance, obesity, cardiovascular disease, and hyperlipidemia. It is has been shown that many of the sequelae of PCOS can be improved by interventions that reduce insulin levels. Previous research has demonstrated that weight reduction and metformin are beneficial in restoring normal ovulation patterns and fertility and can improve hyperandrogenemia and hyperlipidemia. Studies of the effect of lifestyle modifications in women with PCOS have shown that exercise, alone or in combination with changes in diet, can improve ovulation rates and metabolic parameters, and is associated with reduced incidence of insulin resistance. As such, the care of PCOS patients often includes counseling regarding reducing dietary intake and improvement in physical fitness. However, the type of exercise evaluated was inconsistent between many of these studies and varied in intensity, frequency and duration. Therefore, the exercise needed to achieve health benefits in PCOS is not well defined. The Department of Health and Human Services (DHHS) recommends that all Americans get at least 150 minutes per week of moderate aerobic exercise or at least 75 minutes per week of vigorous aerobic activity to maintain health and fitness for all Americans. A critical unanswered question is whether one of these options (moderate versus vigorous) provides superior benefits to women with PCOS.

High-intensity interval training (HIIT) is a form of exercise that combines short intervals of vigorous exercise with lower intensity recovery periods. HIIT has been used as a training modality for high-performance athletes for over a decade. More recently, it has been studied for therapeutic purposes in adults with cardiovascular disease, obesity, and metabolic syndrome. These data suggest that when compared to moderate exercise, HIIT shows greater improvement in aerobic capacity, maximal oxygen consumption, indices of insulin resistance, hyperglycemia, and lipid profiles. HIIT has also been compared with moderate-intensity exercise in patients with type 2 diabetes and has shown a reduction in hyperglycemia, though the data have been controversial. HIIT has not been studied specifically in patients with PCOS.

Studies employing structured exercise programs often have a high drop-out rate and poor post-study continuation rate. An exercise program that requires a fitness facility or other equipment may create a barrier to patient compliance. Additionally, time constraints are often cited as a reason for patient drop-out. Our goal is to create an effective exercise program that can be completed in or around the home, requiring only 15-30 minutes per day.

Participants will be randomized to either 15 minutes of vigorous exercise (HIIT) or 30 minutes of moderate exercise (brisk walking) to be performed 5 days per week for 8 weeks. Exercise training will be performed by an exercise physiologist and participants will then complete their exercise programs independently, using heart rate monitoring and exercise diaries to record exercise intensity. This study will evaluate the feasibility of these exercise plans in terms of patient compliance and safety. We will also evaluate the effect of short-duration, vigorous exercise versus longer-duration, moderate exercise on secondary outcomes such as insulin resistance and metabolic parameters.