If you follow my social media you’ll know last month I spent a weekend in Melbourne with 3 lovely ladies who are inside my HER Biz group. This is a very casual group where we meet monthly to discuss business topics and problem solve issues they are each having. These practitioners have spent time inside my mentorship and have now built their own women’s health business/service and are spending time and energy developing this to truly serve the women in their community.
This weekend was the first time we have ever met in person! After 3 years of being in zoom calls with each other it was so nice to finally meet in the flesh. And let me reassure you I did not get catfished… which did actually cross my mind.
I had originally planned a few things to do that included business strategy and prep for 2025 as well as some women’s health educational material. We had such a good time that we ended up sipping delicious coffee in the streets of Melbourne and eating at top notch cafes and did not end up doing anything else. It was fabulous!
BUT… In preparation for the weekend I prepped a few things we could discuss in regard to women’s health and one of the topics was fertility health and exercise. I work very closely with a fertility dietician and see a fair few clients who are trying to conceive and/or undergoing IVF. There is very little research in this field and I am getting more and more questions from fellow EP’s about exercise interventions that help this population.
I came across this mini review a while ago and found it extremely helpful for guiding my exercise prescription inside the virtual clinic and thought it would be a great paper to share with you.
Paper details → M Mussawar, A Balsom, J Zepetnek, J Gordon (2023). The effect of physical activity on fertility: a mini-review. Fertility and Sterility Reports 4(2) 150-158 https://doi.org/10.1016/j.xfre.2023.04.005
The purpose of the review was to provide current understanding of Exercise and its impact on fertility and recommendations on modifications to exercise where needed.
This review broke down the available research into 3 cohorts of people:
- Healthy women trying to conceive – they were presumed to be fertile
- Women with diagnosed PCOS
- Women undergoing assisted reproductive technologies – in particular IVF
The findings inside the review were as follows…
Healthy women trying to conceive:
- One study looking at runners reported 58% of regular runners (compared to 9% of sedentary women) were found to show menstrual cycle abnormalities. This included presentations of anovulation and insufficient luteal phase (less than 10 days in duration).
- In those who were ovulating and had sufficient luteal phase length, runners had lower levels of progesterone compared to sedentary women.
- Runners also showed lower levels of urinary metabolites of estradiol during the late luteal phase suggesting a possible inhibitory effect of exercise on follicle maturation
- Energy balance was associated with parameters measured in the studies and was important to consider for fertility optimisation.
- Anovulatory cycles were associated with lower energy balance than other types of cycles.
- Women who undertook 2 hours per week of vigorous exercise were 16% less likely to fall pregnant compared to sedentary women even when adjusted for BMI and number of healthy behaviours.
- This % increases as time in vig exercise increases
- Moderate exercise increased the odds of conceiving with just 2 hours per week increasing chances of pregnancy by 15 %
- Women who self reported higher levels of physical activity were 1.5 times more likely to experience subfertility or involuntary childlessness compared to women with a ‘low PA index’
- Energy deficit hugely impacts fertility and was seen in a study comparing degree of energy deficits across 3 groups (severe, moderate, mild)
- 85% of women assigned to a severe/moderate caloric deficit experienced at least 1 luteal phase defect
- Anovulation was also more prevalent in the moderate/severe group
- Rates of anovulation and luteal phase defects remained low in the mild deficit and control group (no deficit)
- Detrimental effects of vigorous exercise on fertility might be improved through increased calorie intake
Take aways:
- Women wanting to continue vigorous exercise when trying to conceive should increase caloric intake on training days by the number of calories burned during their sessions
- Women with luteal phase defects should replace vigorous exercise with moderate exercise. This may be even more beneficial when done in the follicular phase to ensure adequate follicle maturation
Moving onto a more clinical population…Women diagnosed with PCOS:
Limited studies in this group that look at exercise alone but the following was apparent:
- As little as 30 minutes of vigorous exercise per week can significantly increase chances of conception among overweight women with PCOS
- When comparing vigorous to moderate intensity exercise each hour per week of vigorous intensity exercise was associated with a 7% reduced risk of ovulatory infertility. This remained even after adjusting for BMI
- Exercise regardless of weight reductions over performed diet intervention (with weight loss) in terms of ovulation rates. There is a strong association between vigorous exercise and a lowered risk of ovulatory infertility – YAY for Exercise!
- Systematic review and meta analysis examining health benefits of exercise for PCOS more broadly found:
- Vigorous aerobic and resistance training led to greatest improvements in insulin resistance
- Vigorous intensity had greatest benefits for body mass
- 8/16 studies measuring reproductive outcomes found favourable changes in 1 or more parameters with exercise
- Resistance training appeared to have the greatest reproductive benefits relative to aerobic alone – particularly in relation to free androgen index
- 1 study compared HIIT (4 x 4 min aerobic blocks) with strength training (3 x 10 of 8 exercises) and found strength training led to reductions in anti mullerian hormone (AMH) and the free androgen index (FAI) and increases in sex hormone binding globulin. None of which were seen in the HIIT group
- AMH and FAI are generally higher in those with PCOS and reductions in both can be beneficial for reproductive health
- Increased SHBG reduces free androgen levels, which can also improve symptoms and hormonal profiles in women with PCOS
- 1 study compared HIIT (4 x 4 min aerobic blocks) with strength training (3 x 10 of 8 exercises) and found strength training led to reductions in anti mullerian hormone (AMH) and the free androgen index (FAI) and increases in sex hormone binding globulin. None of which were seen in the HIIT group
- Resistance training appeared to have the greatest reproductive benefits relative to aerobic alone – particularly in relation to free androgen index
- Long term consistent training has the greatest reduction in free androgen. More than 50 hours was associated with these changes.
Take home:
- Vigorous aerobic exercise and resistance training appear to be the most directly related to reproductive benefits
- Maximum benefits may take up to 50 hours (roughly 1 month of mod-vig intensity exercise)
- Exercise benefits fertility through mechanisms other than weight loss. Chances of conceiving are improved even in the absence of weight loss.
Last but not least let’s look at women undergoing ART:
Not a lot in terms of research review so let’s get straight into the take home points:
- Most research has found neither PA duration nor intensity to be associated with fertility-related outcomes.
- PA during IVF has either no effect or a positive effect on pregnancy outcomes
- The potential negative effects of exercise on ovulation during natural cycles are no longer observed when ovulation is pharmacologically regulated
- Women undergoing ART can continue their normal activities.
It was also interesting to note the mini review suggested given the significant benefits of exercise on mental and physical health, highly active women should not be discouraged from engaging in vigorous exercise while trying to conceive.
The paper also states it is important to note that no research has yet explored the relationship between physical activity and endometriosis severity or pregnancy rates in women with this condition. This is super relevant for me due to the number of clients I see with Endometriosis and I would love to see some research in this space.
Well that is a wrap on the research spotlight for the month. A little different from the usual pelvic floor specific content. I wanted to share this because in 2025 there will be a new side to HER Education that dives into other women’s health topics and I want you to feel just as excited about it as I am. Stay tuned for more exciting updates early next year.