The PCOS Professor

View Original

PCOS and Exercise: Which Kind of Exercise Is Best?

Most people who know me know that I love working out. So I’m often asked what the best form of exercise is. I always reply with, “The one you will do consistently.” And I firmly believe this. But if you’re someone who enjoys different kinds of exercise, and in particular, if you’re someone who is troubleshooting a medical issue, some forms of exercise might be better than others, and that is the case for women with polycystic ovary syndrome (PCOS).

This question also comes up specifically for PCOS management because weight gain is a common struggle among females with PCOS. Exercise also affects metabolic health, which is a primary concern for those with PCOS as well.

The good news is that several studies analyze the best exercises for PCOS! Read on for more!

ANY EXERCISE VS. NO EXERCISE FOR WOMEN WITH PCOS

There is a large literature that takes women with PCOS who do not regularly exercise and divides them into a treatment group that starts exercising regularly and a control group that continues on with their sedentary lives. Both before and after the exercise intervention, both groups of women have various metrics of PCOS-related wellness measured. Most of these studies consider aerobic exercise (walking or cycling) at moderate intensity 3 to 5 times per week for anywhere from 4 weeks to a whole year. Harrison et al. (2011) and Benham et al. (2018) provide great summaries of these studies. 

As expected, no exercise intervention ever made the women in the treatment group worse off than those in the control group. 

As might be expected for studies with relatively small sample sizes and heterogeneity across things like compliance, specific training plans, etc., there is some variation in the outcomes found. The majority of studies that measured ovulation rate and menstrual frequency found increases in both of these measures, while those studies that considered menstrual cycle length found decreases in length, demonstrating a positive impact of exercise on improving irregular periods and fertility.

The majority of studies also found reductions in body mass index (BMI), waist-to-hip ratio, and insulin resistance. In short, doing some form of physical activity, regardless of the specific type of exercise, a few times a week consistently beats doing nothing pretty much every time.

Which gets me back to: The best exercise is the one you will do consistently!

But there are also a handful of studies that directly compare two or more kinds of training plans, and these studies shed more light for those who are open to more options.

STEADY STATE AEROBIC EXERCISE VS. HIGH-INTENSITY INTERVAL TRAINING (HIIT)

Patten et al. (2022) recruited 29 women with PCOS to participate in a 12-week exercise intervention. Fourteen of the women were assigned to complete moderate-intensity cardio training (60 - 75% of max heart rate) while fifteen were assigned to complete high-intensity interval training (>90% of max heart rate).

Both groups trained three times per week using a stationary cycle ergometer.

The moderate intensity group reached their target heart rate and then maintained the same heart rate for all of their 45-minute sessions, every week.

The high-intensity interval training group had two different HIIT workouts:

  1. 12 sets of 1-minute intervals at 90 - 100% of max heart rate followed by 1 minute of active recovery. This workout was done twice per week.

  2. 8 sets of 4 minutes at 90 - 95% of max heart rate followed by 2 minutes of active recovery. This workout was done once per week.  

The table below summarizes the results of 12 weeks of each exercise program.

The percent change in various health metrics for women with polycystic ovary syndrome (PCOS) after 12 weeks following either a high intensity interval training (HIIT) program or a moderate intensity training program. “-” indicates that no statistically significant change occurred. No winner listed means that there was no statistically significant difference in the changes experienced between the two groups. Data source: Patten et al. (2022).

Both high intensity interval training and moderate intensity steady state training can improve insulin sensitivity and symptoms of PCOS.

Unsurprisingly, women in both groups experienced increases in VO2 max, although the high-intensity group experienced a larger improvement. Both groups also experienced reductions in waist circumference, with no difference seen between the two groups. The moderate-intensity group experienced a reduction in waist-to-hip ratio while the high-intensity group experienced an increase in lean body mass. 

In terms of insulin sensitivity measures, the moderate-intensity group experienced no statistically significant improvements, but the high-intensity group experienced improvements in fasting glucose levels, glucose uptake, and insulin sensitivity.

The high-intensity group also experienced a reduction in free androgen index and an increase in sex hormone binding globulin (two positive improvements in hormonal balance). No changes were found in either group for testosterone levels or estrogen levels. 

While this study demonstrated that high-intensity interval training led to more positive effects than the moderate-intensity training did, we should keep in mind that the study had a small sample size. When considering metrics with large variability across people, we need larger sample sizes to get a clear picture. It is possible that a larger sample size would have shown more improvements in the moderate-intensity group as well. 

DIET ALONE VS. DIET + AEROBIC EXERCISE VS. DIET + AEROBIC EXERCISE + RESISTANCE TRAINING

Some of you might be thinking, well, I don’t need to exercise because I’ve just started a new healthy diet, and I’m certain it is helping. And it might be! But possibly… you could see more improvements by adding in some exercise as well! Thomson et al. (2008) recruited 94 PCOS-affected women and randomly assigned them to one of three interventions: 

  1. diet only: consuming 1200 - 1450 calories per day

  2. diet + aerobic training: consuming 1200 - 1450 calories per day and performing aerobic exercise 5 times per week consisting of 45 minutes of brisk walking or jogging at 75 - 80% of max heart rate per session

  3. diet + combined training: consuming 1200 - 1450 calories per day, performing aerobic exercise 3 times per week consisting of 45 minutes of brisk walking or jogging at 75 - 80% of max heart rate per session, and performing resistance training 2 times per week. The strength training exercises included bench presses, lat pull-downs, leg presses, knee extensions, and sit-ups.

[Note - these calorie targets are very low, especially for women undertaking training programs. I’m discussing this study because of the limited literature on the topic, and not because I think this diet intervention is optimal.] 

The study followed the women for 20 weeks, taking key measurements at baseline, the midpoint of the study, and after the study.

The table below summarizes the results of the three interventions.

The results of 20 weeks of following either: a diet only plan, a diet and aerobic training plan, or a diet and aerobic + strength training plan among women with polycystic ovary syndrome (PCOS). “-” indicates that no statistically significant change occurred. Data source: Thomson et al. (2008).

All three groups experienced statistically significant reductions in weight by week 10. Both exercise groups experienced additional significant weight loss between weeks 10 and 20, but the diet-only group did not.

While weight decreased for the diet-only group, body fat percentage did not decrease across the 20 weeks because women in this group lost both body fat as well as a similar proportion of lean muscle mass. 

Both exercise groups lost small amounts of lean muscle mass, but less than the diet-only group. The two exercise groups groups experienced reductions in body fat percentage, indicating an improvement in body composition. Similarly, the amount of abdominal fat lost by the two exercise groups was greater than the abdominal fat lost by the diet-only group. Comparing the two exercise groups with each other, there were no statistically significant differences in the body weight and body composition metrics tracked. 

When considering blood pressure, we see the lone difference between the two exercise groups. The combined training group experienced statistically significant reductions in both systolic and diastolic blood pressure at the end of the twenty weeks, while neither of the other two groups did. Considering measures of insulin resistance, both exercise groups experienced reductions in fasting insulin levels and insulin resistance by week 10. The diet group did not experience statistically significant improvements in these metrics until week 20

Interestingly, reductions in total cholesterol and LDL cholesterol levels were experienced by the diet group by week 10, but then they lost these reductions by week 20. Both exercise groups maintained their reductions from week 10 to week 20. 

Lastly, the study considered impacts on hormonal imbalances. Both exercise groups experienced significant reductions in testosterone and increases in sex hormone-binding globulin by week 10 while the diet-only group experienced no improvements in these hormone levels. All three groups experienced reductions in free androgen index.

So from this, we can see that either aerobic training or a combination of aerobic and resistance training beats diet alone, especially when considering the impacts on sex hormones. If you have high blood pressure, adding resistance training appears to be a better choice than just aerobic training. For those without high blood pressure, there may be less benefit from adding in resistance training.

However, I would be curious to see the longer-term effects of resistance training combined with aerobic training when not training under a caloric deficit. Under these conditions, we would expect to see increases in lean body mass over time which should further improve metabolic rate and metabolic health. And indeed, the next study I will discuss suggests this is the case, at least when only resistance training is performed.

DOES RESISTANCE TRAINING ALONE HELP WOMEN WITH PCOS?

As someone who loves lifting weights, I was curious to see if only lifting would lead to health improvements among women with PCOS. There is one lone study that considers lifting alone as an intervention for women with PCOS. I am fairly certain this lack of investigation stems from historical norms about what exercise women “should” do. And I think we should set those norms aside for good!

So I’m excited to highlight this paper by Vizza et al. (2016) which discusses a small pilot study (let’s hope a full randomized control trial is coming!) using 15 women with PCOS. Eight of the women were assigned to a progressive resistance training program.

This program included 2 60-minute sessions per week done under supervision. These supervised strength training sessions included:

  • lat pull-downs

  • leg curls

  • seated rows

  • leg presses

  • chest presses

  • split squats

  • shoulder presses

  • bicep curls

  • tricep extensions

  • abdominal crunches

The participants did 2 to 3 sets of 8 to 12 reps of each movement.

The program also included 2 unsupervised home sessions each week that included:

  • lying external hip rotations

  • side leg raises

  • push-ups on knees

  • wall squats

  • oblique curls

  • bird-dog holds

  • hollow holds

Participants did 3 sets of 10 reps of each movement.

This program continued for 12 weeks, while the women assigned to the control group continued with their normal sedentary lives.

The table below shows the results of the 12 week strength training program.

The results of a 12-week strength training program for women with polycystic ovary syndrome (PCOS). “-” indicates that no statistically significant change occurred. No winner listed means that there was no statistically significant difference in the changes experienced between the two groups. Data source: Vizza et al. (2016).

At the end of 12 weeks, the training group experienced a statistically significant increase in body weight, but this was the result of an increase in lean mass. While the group’s fat mass did not decrease, their waist circumferences decreased by about 2 cm on average. In contrast, the control group experienced no changes in any of their body weight or body composition metrics. 

The training group also experienced reductions in HbA1c, a measure of insulin resistance, and reductions in fasting blood sugar levels. This study found no changes in testosterone, sex hormone binding globulin, or free androgen index. It is unclear if this result differs from the previous study due to the smaller sample size and/or shorter duration of the study or if the lack of aerobic training is driving this result. I would love to see a bigger and longer study undertaken.

This study also included participant-reported subjective measures of well-being. At the end of the 12-week study, the training group reported improvements in their emotional well-being, mental health, and their perceptions of their physical abilities, body weight, and social functioning. I think these results might be the most important of the study. So many women with PCOS struggle with mental health and self-image challenges. Weightlifting can be so empowering for women, and I think this fact often gets overlooked by researchers when choosing which outcomes to measure.

AEROBIC VS. RESISTANCE TRAINING (NOT PCOS-SPECIFIC)

To round this out, I really wanted to find a study that compared aerobic training only vs. resistance training only (and ideally a study that compared high intensity interval training vs. steady state aerobic vs. resistance training. Maybe someday!). I was unable to find such a study that recruits women with PCOS. However, there are two interesting studies that are likely applicable to women with PCOS. 

The first study recruited 251 sedentary adults with type 2 diabetes (yes, this is a much bigger study than those recruiting women with PCOS (Sigal et al. 2007). Health issues that affect men tend to get more funding….). They split this sample into four groups:

  1. Control group: continuing their sedentary lives as normal

  2. Aerobic training only: 45 minutes on treadmills or stationary bicycles per session at 75% of max heart rate

  3. Resistance training only: 2 - 3 sets of 7 - 9 reps of 7 exercises on weight machines

  4. Combination of aerobic and resistance training: completed both the aerobic training sessions and resistance training sessions

All training groups trained 3 times per week for 22 weeks. 

At the end of the intervention period, the largest reductions in HbA1c, a measure of insulin resistance, occurred in the combined training group, followed by the aerobic training-only group, and then the resistance training-only group. The control group experienced no changes in HbA1c.

Interestingly, this study found no impact of any training group on blood pressure or cholesterol measures. However, they did find reductions in triglycerides for both the resistance training group and the combined training group. Aerobic training alone did not impact triglyceride levels.

A second study compared training modalities in a sample of 234 adults without a history of diabetes, hypertension, or coronary heart disease (Slentz et al. 2011). All had mild to moderately elevated LDL cholesterol or triglycerides and BMIs between 25 (the threshold for being overweight) to 35 (moderately obese). The participants were randomly assigned to one of three groups:

  1. Resistance training: 3 sets of 8 - 12 reps on 8 weightlifting machines performed 3 times per week.

  2. Aerobic training: approximately 4 miles of jogging per session at 75% of peak VO2 max.

  3. Combined resistance and aerobic training: followed both of the programs described above.

Each group had 4 weeks of ramping up to the programs described above and then maintained those programs for 8 months. 

At the end of the 8 months of training, the resistance-only group experienced about a 1.5lb increase in body weight while the other two groups both lost about 4.5lbs. Similarly, the aerobic group and combined group experienced reductions in subcutaneous and total abdominal fat, while the resistance only group did not experience changes in these measures. 

When considering insulin resistance, the resistance training only group experienced no improvement while the aerobic only and combined groups experienced improvements, with a slightly higher improvement experienced by the combined group.

In both of these studies, the combined group experienced marginally larger improvements than the aerobic only group. Unfortunately, due to the design of the studies, we cannot determine whether this is due to the additional time spent exercising (because the combined group followed both programs in their entirety in both studies) or due to the addition of resistance training specifically. Hopefully more studies will be undertaken where the combined group has the same training duration as the aerobic or resistance only training groups.

TAKE HOME POINTS

Some exercise beats no exercise. Do something! Possible improvements include improved body composition and menstrual cycle regularity and reduced insulin resistance.

Improvements can be found with as few as three exercise sessions per week. Most studies consider 3 to 5 sessions per week.

Me, circa 2018, when I used to compete in crossfit competitions on occasion.

If you love lifting, then lift. If you love aerobic training, do aerobic training.

If you love both lifting and aerobic training, this combination will likely have the greatest impact of all the options. 

And while there isn’t a study to confirm this, considering results across studies, high-intensity interval training with resistance training is likely the best combination of all. 

This might be why CrossFit training seems to have kept the majority of health issues at bay for me. It’s the magical combination of high-intensity interval training, the occasional steady-state aerobic training, and weightlifting. If it’s something you think you’d like, give it a try! If not, find something else that you love, and stick with it!

I’d love to hear about your experiences using exercise to manage PCOS symptoms and health concerns! Feel free to leave a comment below.

See this form in the original post

references

Benham JL, Yamamoto JM, Friedenreich CM, Rabi DM, and Sigal RJ. 2018. Role of exercise training in polycystic ovary syndrome: a systematic review and meta-analysis. Clinical Obesity 8: 275–284, doi: https://10.1111/cob.12258

Harrison CL, Lombard CB, Moran LJ, and Teede HJ. 2011. Exercise therapy in polycystic ovary syndrome: a systematic review. Human Reproduction Update 17(2):171–183.

Patten RK, McIlvenna LC, Levinger I, Garnham AP, Shorakae S, Parker AG, McAinch AJ, Rodgers RJ, Hiam D, Moreno-Asso A, and Stepto NK. 2022. High-intensity training elicits greater improvements in cardio-metabolic and reproductive outcomes than moderate-intensity training in women with polycystic ovary syndrome: A randomized clinical trial. Human Reproduction 37(5):1018–1029, https://doi.org/10.1093/humrep/deac047

Sigal RJ, Kenny GP, Boule ́NG, Wells GA, Prud’homme D, Fortier M, Reid RD, Tulloch H, Coyle D, Phillips P, Jennings A, and Jaffey J. 2007. Effects of aerobic training, resistance training, or both on glycemic control in type 2 diabetes: A randomized trial Annals of Internal Medicine 147(6):357-369. doi: https://10.7326/0003-4819-147-6-200709180-00005

Slentz CA, Bateman LA, Willis LH, Shields T, Tanner CJ, Piner LW, Haw VH, Muehlbauer MJ, Samsa GP, Nelson RC, Huffman KM, Bales CW, Houmard JA, and Kraus WE. 2011. Effects of aerobic vs. resistance training on visceral and liver fat stores, liver enzymes, and insulin resistance by HOMA in overweight adults from STRRIDE AT/RT. Am J Physiol Endocrinol Metab 301: E1033–E1039. doi:10.1152/ajpendo.00291.2011.

Thomson RL, Buckley JD, Noakes M, Clifton PM, Norman RJ, and Brinkworth GD. 2008. The Effect of a Hypocaloric Diet with and without Exercise Training on Body Composition, Cardiometabolic Risk Profile, and Reproductive Function in Overweight and Obese Women with Polycystic Ovary Syndrome. J Clin Endocrinol Metab, 93(9):3373–3380. doi: https://10.1210/jc.2008-0751.

Vizza L, Smith CA, Swaraj S, Agho K, and Cheema BS. 2016. The feasibility of progressive resistance training in women with polycystic ovary syndrome: A pilot randomized controlled trial. BMC Sports Science, Medicine and Rehabilitation 8:14, doi: https://10.1186/s13102-016-0039-8.

Disclaimer: This post is not intended to diagnose or treat any medical issues. It is intended for informational purposes only. I am not a medical practitioner. Always consult a trusted healthcare provider with any questions you may have about a medical condition or treatment and before starting any new health care regimen.