The relationship between Nutrition, Exercise and Female Hormones

Historically much of the research on nutrition and exercise has been conducted on males & it is only more recently that we have seen an emergence of research based on females thanks to (amongst others) Dr Stacy Sims who is a Nutrition & Fitness expert for Women. I have been listening to Dr Stacy Simms’ most recent advice around nutrition & exercise & have summarised some of the key messages that I hope will help you better navigate your health and fitness journey.

Recent study findings

A key finding that has emerged from these recent studies on exercise in women is:

There is a more complex relationship between female hormones (notably oestrogen, thyroid, Kisspeptin and something called Luteinising flux) which means we respond differently to exercise than males, and moreover those responses will change with the hormonal changes during Perimenopause & at Menopause.

Fasted Exercise

Exercising in a fasted state for women increases our cortisol levels but down regulates other key hormones including thyroid hormone & places us in an catabolic (breaking down state) as opposed to an anabolic state (growth and repair state).

Therefore exercising without the proper fuel our body needs, inhibits the very benefits we should be getting from exercising such as improved body composition, enhanced performance, brain function & thyroid function.

Are you fasting before you exercise in the belief that it will help you lose more weight/burn more fat? Turns out that this actually causes greater stress on the body, causing your cortisol levels to rise which in turn affects other hormones especially your thyroid hormone, which is key for supporting metabolism and fat burning.

At Perimenopause baseline cortisol levels tend to be higher so whilst it may seem counter intuitive as you try to burn excess weight you are gaining around the middle at this life stage, fasting before exercise at Perimenopause is unlikely to give you the results you are looking for.

In fact because our hormone responses are linked, you are not only lessening your chances of achieving your desired weight / body composition, you will likely be increasing cravings, affecting your brain function (feeling “wired but tired” sound familiar?) & rather than building & maintaining muscle mass (an anabolic state), your body will be in a catabolic state losing muscle mass.

Adjusting exercise during Perimenopause

At Perimenopause when we are losing oestrogen (which is anti-inflammatory) in order to protect our brain health, bone health & muscle mass and to live healthy & independent lives into our 80s and 90s we need to change the way we exercise by training heavier, with short high intensity intervals & ideally some impact exercises such as skipping or jumping if the body allows us to!

Eating before and after exercise

For reasons that I have explained above, the recommendation is for females to eat before they exercise, usually 1 to 1 and a half hours beforehand is optimal but obviously this will depend to some extent on your daily schedule / commitments.

Dr Stacy Simms provides some useful guidance as follows:

Eating before Training

For Strength Training you need only 15g protein beforehand & if you train early in the morning or generally find you cannot digest too much whole food beforehand, mix 15g protein powder with unsweetened almond milk.

For High Intensity Interval Training use sweetened almond milk with protein powder.

For Endurance Training you will need to add 30g of carbohydrates to the above so maybe a banana or berries and honey or some frozen pineapple chunks.

Eating Post Training

The ideal window for maintaining lean muscle mass, repairing and rebuilding (remember putting us in an anabolic state) & importantly getting the most benefit from our exercise is within 1 hour.

Protein Guidelines

Protein is the key macronutrient here & how much will depend on our age but again Dr Stasy Simms recommends the following:

During our Reproductive years

Aim for 35g protein preferably food based from meat, fish, eggs, beans & pulses, tofu /tempeh.

At Perimenopause

Aim for between 40g-60g protein again preferably food based but to hit the higher target you may want to combine food and a protein powder.

This higher amount is due to changes in the way our body is metabolising foods (less oestrogen affects insulin responses, our blood sugar handling as well as fat distribution).

Carbohydrate Guidelines

Carbohydrate is the other key macronutrient post training as it helps to replenish the glycogen stores that are depleted during training & can help prevent your body from breaking down muscle tissue for energy, again important if we want to get the most gains for our effort.

The window for consuming carbohydrates post training according to Dr Stacey Simms is longer than for protein – within 2 hours, although you can of course combine these in one meal & is roughly based on 3g per Kg of body weight.

Carbohydrate sources include sweet potato, basmati rice, rice noodles, quinoa, amaranth and all vegetables and fruits.

Exercise During Menstruation

There have been some conflicting results on this which may be explained in part by the fact that menstrual cycles differ widely between females. The advice is primarily based upon the timing of ovulation but this may not be that helpful as it is reported that for menstruating females at least 3 out of 12 monthly periods in a year may be anovulatory i.e. no ovulation.

So – the key message here is to listen to your body, be intuitive – dialling into your own monthly patterns but for all the reasons above ensure that you fuel for exercise.

And one thing to note – the week before your period if you are hungrier, eat more protein and especially carbs before training to ensure you are not raising your cortisol levels too high which will activate your “flight or fight response” and a catabolic state as described above.

Sauna use after Exercise

Dr Stacy Simms explains that heat exposure for females leads to better body composition adaptations (in terms of our insulin & glucose response, enhanced muscle metabolism) than ice cold exposure.

IF you have access to a sauna (infra-red or traditional Nordic) then taking a sauna for up to 30 minutes soon after exercise has been found to be beneficial and could help with your hot flushes too if you are experiencing these.

Sleep and Exercise

Focusing on your sleep to support your training may be more important during the second half of your cycle (mid luteal phase to pre menstruation) due to changes in oestrogen levels which directly influence and are linked to changes in our serotonin and melatonin (sleep hormone) levels.

At this time your slow wave sleep changes, you experience less deep recovery sleep as well as finding it harder to get to sleep so it at this time when you need to be especially focused on the best sleep hygiene practises including the use of Non Sleep Deep Rest or Yoga Nidra exercises.

Supplementation for Exercise

The following are key if you exercise regularly:

Creatine

3-5g daily especially for women 50+ to prevent muscle loss, increase bone strength and for mood and cognition.

Vitamin D3

(Preferably with Vitamin K) to support bone health, our immune system, reduce inflammation and for absorption & maintenance of Iron stores.

Protein Powder

I also recommend having a quality protein powder to supplement your food intake as some days it is hard to eat the required amount of protein especially if you have a sweet rather than savoury breakfast.

Adaptogens

These plant based supplements which boost our stress response can be helpful in supporting women’s nervous system ensuring we are more frequently in a “restore and repair state” as well as ensuring better sleep.

Summary

Women have hormones which fluctuate during our monthly cycles & change as we enter perimenopause and reach menopause.
Being aware of the impact / influence will help us to make the most gains from exercising during our reproductive years and importantly – adapting our training habits at perimenopause & beyond will help maintain our bone health, brain health, propioception and metabolic health to live independent & healthy lives into our 80s and 90s.