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Does strength training affect fertility?

Posted by for Wellbeing

Does strength training affect fertility? A well-informed approach to weight lifting and exercise could be conducive to successfully conceiving. Here’s what you need to know if you’re trying to get pregnant. 

The topic of fertility is, more often than not, characterised by an undercurrent of anxiety. What should we eat when trying to fall pregnant? Can we drink alcohol while trying to conceive? What’s the best way to exercise and will it affect ovulation? There’s no one-size-fits-all answer, which likely explains why one in seven couples in the UK struggle to conceive. What we do know, though, is that strength training can help – but it comes with caveats.

Women’s sport and exercise medicine registrar Dr Amal Hassan, obstetrics and gynaecology doctor Dr Brooke Vandermolen, fertility and women’s health expert Emma Cannon, and Rosie Stockley, founder of pregnancy and postpartum fitness programme the MAMAWELL Method have joined forces to help us debunk the myths and bring you the next best thing to a fertility fitness blueprint.

How can strength training affect fertility?

While we’re not ones to rely on the scales, weight was a recurring theme within our experts’ answers.

“Being in the healthy weight range reduces the risk of infertility and improves the chance of conceiving spontaneously and with assisted reproductive technology (ART),” Emma explains.

Research concurs, with a study published by the American Society for Reproductive Medicine in 2016 revealing that women classified as ‘obese’ were less likely to conceive naturally.

Rosie, meanwhile, refers to the relevance of a menstrual cycle when trying to conceive (you’re not producing eggs otherwise): “In order to maintain a regular cycle, oestrogen needs to be made and being underweight could affect the production of this hormone. Be mindful of calorie intake and ensure a BMI of 18.5-24.5.” The NHS’ BMI calculator will offer a more precise number. In other words, overexercising could “result in a loss of the menstrual cycle and therefore, ovulation”, Emma explains.

Weight management also applies to anyone going through IVF. Dr Brooke Vandermolen referred to this 2018 study, showing that physically active women of a normal weight had better assisted reproductive outcomes.

Granted, weight can be controlled with all types of exercise, so what about strength training in particular?

Dr Amal Hassan reports blood sugar control as one of the most positive physiological effects. “Insulin insensitivity – when the body’s cells don’t recognise the signalling of insulin to take up glucose from the blood and use it for energy – is linked to infertility,” she tells us. “Strength training can positively influence this, as well as other markers of cardiovascular health including resting blood pressure rate and your cholesterol profile.” She adds that these contribute to both a successful conception, and a healthy pregnancy.

Can too much exercise decrease fertility?

The American Society for Reproductive Medicine used exercise as a variable within their investigation. The ‘overweight’ category was required to take part in ‘vigorous’ physical activity, while those in the ‘normal’ range completed ‘moderate’ movement (where “you should still be able to talk without pausing for breath,” says Dr Brooke). Both groups showed an improvement in reproductive rate, but it could be detrimental to continue with intense exercise once you have reached the ideal weight for your height, age and how active you are.

Emma says: “High intensity exercise signals to the body that we are not safe, resulting in us activating the fight and flight response. For fertility, we need to be in feed and breed mode to indicate we are not in danger and the environment is safe. I definitely see a correlation between excessive exercise and a reduction in fertility. Moderate exercise has the opposite effect and can actually help regulate the menstrual cycle, reduce pain and improve mood.”

As with all of our points, Dr Amal affirms that the definition of “too much” will vary from person to person. “It’s dependent on a number of factors,” she explains. “Not limited to how conditioned you are to the exercise you’re doing, and the time it’s taken you to reach your current load.”

She recommends looking to signs you’re overdoing it: irregular, increasingly light or completely absent periods; recurrent injuries – usually bone stress; significant weight loss in the context of under-nutrition; poor performance and insufficient recovery.

“These features, usually in combination, signal that the body has limited energy reserves to allow ovulation to occur,” she concludes.

Dr Brooke also reiterates how strenuous exercise could affect the hormones responsible for your periods, while in 2018, another study was published whereby women who engaged in vigorous workouts for over 60 minutes per day were more likely to stop ovulating.

Can I lift weights while trying to conceive?

“Do what you’ve always done,” says Dr Amal. Even if you’ve never lifted a dumbbell in your life, trying to conceive shouldn’t deter you – just adopt a less-is-more approach. “Nail your neuromuscular strength, ie bodyweight training first,” Dr Amal suggests. Remember to avoid “increases in load and intensity to avoid injury, recover well and fuel and refuel appropriately”.

Rosie touts the mental gains, too. “The average woman will enjoy the confidence, strength and positive endorphins that keeping strong can bring,” she says.

 The only exception is anyone going through IVF. There is no scientific research to confirm that it has an impact, but Rosie tells us that long walks and mindfulness exercises may be more beneficial during such an intense treatment.

Emma agrees that you might want to hold off on the heavy lifting, and references a study whereby women who did four hours of strenuous exercise per week while going through IVF had a lower reproductive success rate. Instead, she proposes yoga, walking, swimming, and Pilates, as well as belly dancing, which she tells us “helps with the flow of blood in the uterus”.

Can I do squats while trying to conceive?

Absolutely. Strength in the abdominal region could translate to an easier labour, especially when combined with regular pelvic floor exercises, so says Dr Amal.

The overriding ethos from current research is that there is no need to stop performing moves that you’re already akin to when trying to conceive – nor when you are pregnant. Though Dr Brooke says you may need to “modify your range of motion” to accommodate a baby bump.

What are the best ways to boost fertility with exercise?

The goal across both the scientific and holistic schools of thought is to create the optimal environment to harbour a baby. Think about it. You wouldn’t want to spend nine months somewhere that felt weak and vulnerable – nor does an embryo.

The physiological requirements, as shared by both Dr Brooke and Dr Amal, include remaining active, “eating appropriately for energy and building in adequate recovery via rest and nutrition”. Just one missing link will have a “significant effect on fertility”. As for supplements, Dr Amal recommends taking 400mcg of folic acid and 1000iU of vitamin D daily, but asserts that these are not a replacement for staying active.

At the heart of psychological studies regarding fertility and fitness is stress. “Enjoyment in exercise and finding ways to manage stress and anxiety are important considerations,” Emma says, while a paper from 2018 showed that the reproductive rate of participants increased when mental distress was lowered. Rosie backs this up, advising that when the stress hormone cortisol is reduced, the rate of blood flow and oxygen to the mind and body spikes.

So while the process of trying to fall pregnant can be one of the most stressful in a woman’s life, know that movement and exercise can help. 

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IMAGE: Getty 

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