Many women fear the onset of their cycle.
It often comes with discomfort, irritability, cramps, and cravings.
The constant fluctuations in hormone levels mean that everything from your energy levels and strength, to your appetite and mood, can change from one day to the next.
And whilst a regular cycle is a sign that you are healthy, many women feel it affects their weight loss or activity levels because of these symptoms.
Being aware of how your cycle affects your appetite and energy, your endurance, strength and ability to tolerate exercise training, allows you to take advantage of the many biological ‘windows of opportunity’ that are presented to you along the route of your monthly cycle.
Knowing how to adapt your workouts and diet can play an important role in fat loss, athletic performance and muscle build.
Your menstrual cycle isn’t an excuse to skip sessions; it’s simply an opportunity to switch your approach and optimise your body composition through training knowledge.
Here’s everything you need to know…
CYCLE BASICS
The most obvious place to start is to look at exactly what happens over the course of a typical cycle.
And I say that through gritted teeth, because I know from experience that a ‘normal’ cycle for one woman is much different to another.
If you are well familiar of the sequence and length of each cycle, feel free to skip to the diet and exercise recommendations.
Whilst some women might have a steady month-to-month cycle, many women experience phase-to-phase variations where cycles last anywhere from 21 days to 35.
And some women of course either have stopped their periods (menopause) or suffer irregular periods because of hormonal disturbances or medications.
However, when you look at the collective data, the average monthly cycle is 28-day long, so for the purpose of this section that’s the context we’ll use.
How hormones shift week by week
Although there’s a lot of changes to hormones over the month, we’ll focus here on the ones that affect training and nutrition the most – namely
- Estrogen
- Progesterone
- Testosterone
- Luteinizing Hormone
Although there’s a fair bit of biology involved here, it’s important to understand this going forward so that you can best manipulate training and nutrition to suit your body.
Presuming that your cycle is normal, there are three main phases that occur over the 28-day cycle period. A cycle is counted from the first day of one period to the first day of the next period. Here’s what you can expect.
1. The follicular phase – Days 0-14
Because each phase rolls on from the one preceding it (they occur as a perpetual cycle), there’s no real start or end point. However, it makes sense to look at the follicular phase first as it is when menstrual bleeding begins so gives us a big landmark at which to count the days.
2. Ovulation – Day 14
Roughly between days 13 and 16, ovulation occurs. During this short phase, the egg is ushered towards the fallopian tube because of an increase in blood flow and connective tissue contraction.
3. The luteal phase – Days 15-28
This phase – otherwise referred to as premenstrual phase – is the gap between ovulation and bleeding.
THE IMPACT OF MENSTRUAL CYCLES ON PERFORMANCE
According to one research paper, “Women’s weight and body composition is significantly influenced by the female sex-steroid hormones.
Levels of these hormones fluctuate in a defined manner throughout the menstrual cycle and interact to modulate energy homeostasis” [1].
Changes in Body Temperature, Time to Exhaustion and Fatigue
The monthly menstrual cycle isn’t just associated with rhythmic changes in hormone levels; it is also accompanied by changes in autonomic thermoregulation – fluctuations in core body temperature [2].
Again, although this might differ from woman to woman, the typical pattern of temperature changes seem to be similar across the 28 days.
Post-ovulatory increase in body temperature
Firstly, there doesn’t appear to be any change in body temperature during the early or late follicular phases.
This means that the body is regulated at a normal 36-37 degree Celsius. Couple this with the increase in estrogen, and chances are you’ll feel full of energy and your mood will be positive too.
However, shortly after ovulation when progesterone is on the increase, there is a gradual elevation in body temperature.
It is more evident in the morning but will facilitate itself throughout the luteal phase [3]. This can lead to poor thermoregulation and feelings of excessive heat, particularly when exercising.
You might feel more fatigued than normal
The rise in temperature during the luteal phase may mean you feel warmer during your workouts, or run the risk of acute dehydration through perspiring.
Current consensus suggests that there may also be a decrease in time to exhaustion too – you’ll tire much quicker than during the follicular phase.
This is more than likely due to an increase in general cardiac strain [4]. Like anything, it is important to monitor how you feel during your workouts and adapt according to individual tolerance.
Pain tolerance
While we might not necessarily have the absolute strength of our male counterparts (on average), we can tolerate much higher submaximal volume… and can recover much more efficiently between sets too.
Especially during the follicular phase we can often tolerate more pain.
This can lead to favorable increases in strength and tolerance at high intensities.
Ramping up total session volume and decreasing rest periods is a good way forward.
Exercise performance
The majority of data currently suggests that there is no change in maximal oxygen uptake, heart and ventilation rate or blood volume at various time points across the menstrual cycle. There is, however, a big difference in perceived exercise stress.
If you were to do the exact same workout over the two phases, it may feel harder in the luteal phase.
HOW DO YOU OPTIMIZE PERFORMANCE FOR FAT LOSS
Ramp up the intensity during the follicular phase.
The follicular phase has so far pointed to an increase in pain tolerance, normal body thermoregulation, and limited potential fatigue.
But with all of those positives comes the negative… you might find that your metabolic rate is slower here than in the post-ovulatory period.
Some studies showing that your resting energy expenditure can be at its lowest around one week before ovulation [5] meaning a dip during the follicular phase.
During the late follicular phase, testosterone and estrogen are both relatively high, while progesterone is still quite low.
Testosterone, as we know, is an anabolic hormone that promotes strength.
Estrogen itself also has anti-catabolic properties that reduce muscle damage and promote recovery.
Progesterone though is a catabolic hormone that can counteract the effects of both testosterone and estrogen.
This means you’re in a great place to really push yourself and hit the gym for some high-intensity strength and cardio work.
The estrogen to progesterone ratio is in your favour to make some big gains and you’ll feel strong.
Research also suggests that weight training in the follicular phase results in higher increases in muscle growth than in the luteal phase too [6].
This is more than likely due to higher circulating anabolic hormone levels.
And with the high capacity for adaptation, you’ll soon be rewarded for your hard work with some big gains.
Racking up the intensity in your strength training is perfect at this time to hep you to boost your lean mass and change your body composition.
Focus on what your body needs and wants to do during the luteal phase
As ovulation passes and you move into the luteal phase you’ll notice that your metabolic rate begins to pick up again.
Your force capacity and strength will likely begin to taper off. In this phase, progesterone levels peak, meaning your response to strength training won’t be as high.
Unfortunately, your basal body temperature begins to increase and pain tolerance isn’t as high, so don’t expect to be setting any PRs on the big lifts.
You don’t have to stop strength training (and you shouldn’t), but just be aware that you might not feel as strong and your perception of how hard your sessions are will go up.
A good plan here would be to take the foot off the gas a little and really listen to what your body wants to do at this time.
Maybe you'd like to go for an easy bike ride instead?
Or partake in a pilates class? Deload strength sessions and endurance sessions with an emphasis on duration and not intensity also work well here.
THE IMPACT OF THE MENSTRUAL CYCLE ON DIETING
How to eat around your cycle
During your period:
- Eat iron-rich foods to help with fatigue and replenish the blood lost. This includes beef, lamb, eggs, leafy green vegetables, chickpeas, lentils and quinoa.
- Vitamin B12 has an essential role in supporting healthy blood cells, nerve cells and DNA production. It is readily available in animal sources of protein including meat, chicken, fish, eggs and yoghurt. B-12 fortified foods are also available if you are searching for plant-based sources of B12. This includes some nutritional yeast, vegetarian sausages, plant-based soy milk or almond milk.
- Fibre and Water – Changes in estrogen and progesterone can contribute to constipation leading up or during your period. To prevent this, continue to have fibre-rich foods including fruit, vegetables, wholegrains, legumes and beans with plenty of water.
- Magnesium-rich foods: There is some research highlighting that magnesium may alleviate period pain, cramps and migraines. Magnesium in combination with vitamin B6 increases the effectiveness of reducing PMS symptoms including anxiety, irritability, depression, headache, nausea, and pain. Magnesium rich foods include dark leafy greens, nuts, seeds, fish, beans and legumes, whole grains, avocados, and low-fat dairy. Foods that are high in vitamin B6 include pork, chicken. Turkey, soy, oats, bananas, milk and fish.
- Avoid processed salty foods or highly processed carbs– If you want to minimise bloating on your period, you can reduce your intake of processed salty or sugary foods. Generally, they cause you to hold onto more water and cause you to feel more bloated than usual. Adding a bit of sea salt to your home cooked meals is fine.
Insulin sensitivity and cravings
Because your insulin sensitivity is much lower in the luteal phase (and consequently your blood sugar is less stable), you’ll probably begin to get cravings for sugary or high-fat foods – basically anything with a high energy density.
You may at this stage already be suffering low mood, and a sugar hit helps to release the mood-regulating neurotransmitter serotonin so the cravings could be pretty strong.
For the most part try to resist these cravings (your body wants you to put on a bit of fat here to ensure you have a bit of extra body fat to bring a healthy child into the world...), but a flexible diet that allows some high-calorie foods whilst still maintaining a deficit is more appropriate here than a strict restrictive dietary approach.
How to manage hunger:
First and foremost make sure you are hitting your protein, fiber and water target. You will notice that this alone will help IMMENSELY with your cravings.
Some women can pretty much pin-point when their cravings will go up every month and do great with calorie cycling, so in anticipation of these cravings they might increase their calories from their usual maintenance of let's say 2000 to 2200 for a week and then the week following their period when hunger is usually lower back down to 1800. So in essence this means 1 high week, 1 low, 2 medium.
Leading up to ovulation:
Consume more foods high in folate in order to help your body form healthy blood cells (so leafy greens, broccoli, chickpeas, kidney beans...)
Seed cycling:
Many naturopathic practitioners swear on the practise of seed cycling. This supposedly helps regain or keep cycles regular and minimize unwanted period symptoms.
This is the practice of consuming 1 Tbsp of ground flaxseeds and 1Tbsp of pumpkin seeds day 1-14 of your cycle and 1Tbsp of sunflower and 1 Tbsp of sesame seeds day 15-28.
Water retention
Many women complain about water retention throughout their cycle.
And although it affects each woman differently, fluid retention commonly occurs when progesterone is high – in the luteal phase.
This will more than likely make you heavier on the scales due to excess water weight.
Pre-menstrual syndrome (PMS), which is characterised by irritability, emotional tension and water retention, are common symptoms right before your period (4-7 days beforehand for most women). Fluid retention can also occur pre-ovulation too in some women.
Once your period starts and your body temperature returns to normal your water retention will begin to disappear and your body mass will regulate.
When to weigh yourself
Although scale weight isn’t the whole story of fat loss, it may still be important to chart progress, particularly in those who are overweight and wish to achieve a healthy body mass.
It goes without saying that weight loss and weight gain won’t be linear over the duration of your cycle. Water weight alone can fluctuate massively and send the dial on the scales spinning in all directions.
It is recommended that a seven-day rolling average of your weight is taken to chart progress, rather than a week-by-week differences. This takes into account water retention and hormonal changes that can compound changes to body fat and muscle mass.
It is also useful to compare measurements from one phase to the next, for example looking at body weight in early follicular phase one month, then looking at differences in the same phase the following month.
Are there any supplements you should consider?
It is important that you prioritize getting all of your nutrients from food sources before considering adding in supplementation.
That said, there are a small number of supplementary nutrients that you can cycle into your menstralean diet to optimise fat loss.
- Vitamin D – important for bone and cardiovascular health. Recommended doses for trained athletes are variable, but about 4000-5000 IU per day seems most appropriate.
- Iron – if you have a heavy flow, a deficiency can really affect your performance, thyroid function and anemia.
- Calcium – important to promote fat loss and bone health. Splitting doses of ~1200 mg total per day seems to work well.
- Magnesium – 400 mg of magnesium citrate may help to alleviate symptoms of PMS and improve sleep
Menstrual disruptions – not all women are the same
As well as person-by-person variance on the timings of each phase, you may also experience menstrual disturbances – times when your period becomes irregular or even stops.
Firstly, hormonal birth control pills cause menstrual disturbance, as they block ovulation by inhibiting the LH surge we talked about in the follicular phase. Remember, it is LH that acts as a pin to puncture the follicle and release the egg. This, in turn, blocks menstruation.
Common non-medicine related disturbances include luteal phase defect (where progesterone levels are too low), anovulation (ovulation does not occur), oligomenorrhea (infrequent periods). In the case of each of these, advice needs to be given to the individual and their specific symptoms.
But the most common disturbance is that of amenorrhea.
What is Amenorrhea?
Amenorrhea is the absence or cessation of your period. It is a hormonal disorder with a number of possible root causes.
Who is at risk?
Firstly, those that regularly participate in sports or exercise frequently are at a much higher risk of amenorrhea. Current statistics suggest that 69% of women athletes will experience a loss of cycle due to secondary amenorrhea at some point [10]. This is in comparison to less than 5% for untrained women.
Those that participate in sports that have an emphasis on low body mass such as physique, ballet, gymnastics and diving show highest incidences of all.
Why would you lose your period?
Rapid decreases in body mass and/or body fat seem to be the trigger for a loss of menstrual cycle. A low body mass index, in particular, seems to be a big risk factor.
And low body weight is typically caused by low energy availability – a calorie deficit that is too aggressive, causing a reduction in both fat and fat-free mass.
When low body mass occurs, your hypothalamus doesn’t trigger the pituitary gland to release LH if there’s no trigger from LH there’s no ovulation. This is what’s referred to as functional hypothalamic amenorrhea.
Does dieting affect your period?
Yes. If you achieve a rapid or aggressive calorie deficit and weight loss, you’ll soon inhibit the hypothalamic-initiated release of LH. That, in turn, will reduce ovulation and your period can stop.
It is therefore important to either hit an aggressive calorie deficit for shorter periods of time, or to cruise in more gradually while still being able to train hard in the gym.
Should you be concerned if your period stops?
Not in the short term. A few missed cycles in a dieting phase are not the end of the world.
However, returning to calorie maintenance, consuming healthy fats and keeping your training volume and stress in check are very important for long term health and preventing osteoporosis.
On a final note: Nutrition and exercise play a huge role when it comes to your reproductive health and how you feel throughout your cycle.
Utilize it to your advantage so that you thrive as a women, rather than struggling through the blessings we have been given.
References:
- Davidsen, L et al. Impact of the menstrual cycle on determinants of energy balance: a putative role in weight loss attempts. Int J Obesity. 2007; 12: 1777-85
- Nagashima, K et al. Thermoregulation, and menstrual cycle. Temperature. 2015; 2(3): 320-321
- Garcia, AMC et al. Luteal phase of the menstrual cycle increases sweating rate during exercise. Braz J Med Biol Res. 2006; 39(9): 1255-1261
- Janse de Jonge, XA. Effects of the menstrual cycle on exercise performance. Sports Med. 2003; 33: 833-851
- Solomon, SJ et al. Menstrual cycle and basal metabolic rate in women. Am J Clin Nutr. 36(4): 611-6
- Sung, E et al. Effects of follicular versus luteal phase-based strength training in young women. Springerplus. 2014; 3: 668
- Zderic, TW et al. Glucose kinetics and substrate oxidation during exercise in the follicular and luteal phases. J Appl Physiol. 2001; 90: 447-453
- Ashley, CD et al. Menstrual phase effects on fat and carbohydrate oxidation during prolonged exercise in active females. JEP. 2000; 3(4): 67-73
- Geiker, N et al. A weight-loss program adapted to the menstrual cycle increases weight loss in healthy, overweight, premenopausal women: a 6-mo randomized controlled trial. Am J Clin Nutr. 2017; 105(6)
- Abraham, SF et al. Body weight, exercise and menstrual status among ballet dancers in training. Br J Obstet Gynaecol. 1982; 89(7): 507-10
