Hormones and metabolism in females, part 2.

Following on from my blog last week about hormones in females and their effect on metabolic rate.

During ovulation the body increases its core temperature, leading to increased metabolic rate for 3 or 4 days (an extra 300 calories per day roughly – cool!). So, after menopause we no longer get that added benefit of increased calorie burn for free during a few days of the month.

During menopause the loss of progesterone leads to decreased absorption of vitamins and minerals which can be a factor in insomnia, migraine, food cravings and decreased sex drive. When oestrogen is still dominant, before it starts depleting, mood swings and fluid retention are common. Ensuring you get a varied diet with an emphasis on vitamins B6 (decrease bloating), A, B12, C, and E, and the minerals calcium, magnesium and iron can help with symptoms.

Training to increase strength, and metabolism, requires recruitment of fast twitch muscle fibres, which happens when you can only just perform 8-10 repetitions of an exercise. This is called high intensity weight training, which also increases fat oxidation (fat ‘burning’).

Time under tension is important for GH (growth hormone) release. Optimal timing would be 2 seconds eccentric / muscle lengthening, 1 second hold and 2 seconds concentric / muscle shortening. Each set lasting 40-70 seconds.

Higher intensity weight training also leads to increased caloric expenditure for a few hours following the training bout.

It is very important not to decrease calorie intake too much in the long term when trying to lose body fat. Big reductions leads to the body using lean body mass (muscle) as its fuel. Extreme low calorie intake can also lead to deficiencies in Vitamin B12, and electrolyte and iron absorption.

Limit high intensity cardio exercise to less than 90 minutes, as it becomes a catabolic (muscle breaking down) activity after 90 minutes, which negates your strength training. Cortisol starts to rise and GH declines.

Bone mineral density decreases concurrently with oestrogen loss after menopause.  Bone mineral density is increased via strength training. This is very important to decrease your risk of fractures. Emphasise standing exercises as this increases bone load.

Isometric holds are a great way to increase fast twitch muscle fibre recruitment, for example a held squat for 30 seconds.

After high intensity weight training a 36 hour recovery for that area of the body is beneficial for growth and repair. Cardio exercise is fine during this period.

A few signs that you are training heavy enough to produce GH – SWEATING, GETTING OUT OF BREATH, GETTING HOT, BEING UNABLE TO TO MORE THAN 12 REPS.


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