Testosterone and Endurance



What can lower testosterone and what we can do about it naturally?



Low Testosterone as a result of endurance training

Low levels of testosterone can lead to poor muscle mass development, increased body fat stores, compromised athletic performance, reproductive issues and low libido.

Endurance exercise can contribute to lowered levels of testosterone in men and can affect other important hormones in women. Many of us are avid exercisers that love endurance training so what can we do to ensure that our testosterone and other hormone levels are optimised?

Exercise stress on androgen hormones

Studies consistently show that high-volume endurance exercises reduce baseline androgens by 20-40%. Androgen hormones include testosterone, oestrogen, DHEA. Follicle stimulating hormone (FSH) and luteinising hormone (LH), both male and female hormones, can be affected which may lead to reproductive issues.

In men testosterone, FSH and LH can all be reduced affecting libido and semen quality. Whereas in women typically only LH and FSH are affected which can contribute to fertility problems and menstrual irregularities.

High Cortisol effects on testosterone

Over time repeated bouts of intense, long duration training can lead to adrenal gland enlargement due to higher cortisol outputs. Cortisol, a stress hormone, is produced in larger quantities as a result of endurance training over strength or power training. Cortisol in normal amounts is necessary for metabolic functions however if it is chronically elevated it may lead to an impaired stress response and a decline in testosterone.

Chronically elevated cortisol has a catabolic effect on muscle tissue leading to persistent inflammation and suppressed immune function leaving athletes vulnerable to colds and illnesses during high volume training phases. Fat burning ability is also reduced leading to higher levels of stored body fat.

Scientists believe that an increase in cortisol may inhibit testosterone.

Bone density reduction

Low testosterone has been linked to lower bone density and susceptibility to fractures in endurance athletes.

Low testosterone may interfere with power and hypertrophy

Endurance athletes experience less muscle mass development due to a phenomenon known as ‘interference’ which may be partly due to reduced testosterone and androgen hormones since these hormones play a role in muscle tissue repair. Testosterone increases DNA activity on muscle tissue and leads to a greater release of growth hormone which enhances amino acid uptake and tissue repair.

How can we help to prevent low testosterone?


  1. Follow a well-constructed training program. Speak to your coach, or get a coach that understands how to construct an effective periodised training plan to meet your goals. Your coach will advise you on training and rest and prevent overtraining.
  2. Eat quality fats in the diet. Testosterone is produced in the body out of cholesterol, studies show that healthy fat intakes support testosterone more than restricted fat diets. Choose grass fed meats, oily fish, cold pressed oils, nuts, seeds, avocadoes and olives.
  3. Eat complex, low glycaemic carbohydrates. Carbohydrates support testosterone production as they help to lower cortisol. Choose whole carbohydrates from vegetables, fruit, beans (such as chickpeas, lentils, kidney beans) and grains such as amaranth, quinoa, oats, millet and buckwheat.
  4. Avoid sugars and refined carbohydrates. A diet high in processed carbohydrates such as white flour, processed cereals, cakes, biscuits, frozen convenience meals and takeaway foods are contraindicated due to their high blood sugar response which can temporarily decrease testosterone by 25%. Opt for slower digesting carbs or healthy high glycaemic carbohydrates post workout.
  5. Prioritise sleep. A lack of sleep will further increase cortisol levels and alter testosterone levels and in combination with high levels of endurance training can lead to hormonal dysregulation.
  6. Reduce Stress. Reduce stress wherever possible and practice daily stress reducing techniques such as meditation.

Foods to support production of testosterone and regulation of cortisol (for both men and women)

  • Zinc – liver, beef, sunflower seeds, pumpkin seeds and shellfish (vegetarians and vegans may need further zinc support through supplementation)
  • Vitamin D- Cod liver oil (warning: cod liver oil is rich in vitamin A; too much may be bad for you), tuna canned in water, sardines canned in oil, milk or yogurt -- regardless of whether it's whole, non-fat, or reduced fat - fortified with vitamin D, beef or calf liver, egg yolks, cheese. Daily sunshine on the body without getting sunburn
  • Boron - chickpeas,almonds, beans, vegetables, bananas, walnuts, avocado, broccoli, prunes, oranges, red grapes, apples, raisins, pears, and many other beans and legumes
  • Magnesium- Beans, legumes, nuts, barley, brown rice, cocoa, cod, eggs, figs, kelp, seeds, molasses, leafy greens and wholegrains
  • Vitamin C – Papaya, capsicum, broccoli, brussel sprouts, strawberries, pineapple, oranges, kiwifruit, rockmelon and cauliflower
  • Potassium – Beet greens, lima beans, swiss chard, sweet potato, potatoes, soybeans, spinach, avocado, pinto beans and lentils
  • Tyrosine - cheese, soybeans,beef, lamb, pork, fish, chicken, nuts, seeds, eggs, dairy, beans, and whole grains
  • Vitamin B5 – Chicken liver, sunflower seeds, salmon, avocado, sundried tomatoes, corn, broccoli, mushrooms, cauliflower and yoghurt
  • Manganese – Spices and herbs, wheat germ and bran, hazelnuts, pine nuts, pecans, mussels, oysters, clams, cocoa powder and dark chocolate, roasted pumpkin seeds, flax, sesame seeds and tahini and chilli powder
  • Copper - Oysters and other shellfish, whole grains, beans, nuts, potatoes, and organ meats (kidneys, liver) are good sources of copper. Dark leafy greens, dried fruits such as prunes, cocoa, black pepper, and yeast are also sources of copper in the diet.
  • Healthy fats- Grass fed meats, oily fish, cold pressed oils, nuts, seeds, avocadoes and olives.



West, D., Phillips, S. Associations of Exercise Induced Hormone Profiles and Gains in Strength and Hypertrophy in a Large Cohort after Weight Training. European Journal of Applied Physiology. 2012. 112, 26932702.

Arce, J. Subclinical alterations in hormone and semen profile in athletes. Fertility and Sterility. 1993. 59(2):398404.

Fischbach, F., Dunning, M., eds. Manual of Laboratory and Diagnostic Tests, 8th ed. 2009. Philadelphia: Lippincott Williams and Wilkins.

Hackney, Anthony. Endurance Training and Testosterone Levels. Sports Medicine. 1989. 8(2), 117127.

Hackney, Anthony. Testosterone and Reproductive Dysfunction in Endurance Trained Men. Encyclopedia of Sports Medicine and Science. Internet Society for Sport Science. 20 Sept 1998. http://www.sportsci.org/encyc/testosterone/testosterone.html.

Lac G, Berthon P. Changes in cortisol and testosterone levels and T/C ratio during an endurance competition and recovery. Journal of Sports Medicine and Physical Fitness. 2000. 40(2), 13944

Maclean, C., et al. Effect of the Transcendental Meditation Program on Adaptive Mechanisms: Changes in hormone Levels and Responses to stress After Four Months of Practice. Psychoneuroendocrinology. 1997. 22(4), 277295.

McArdle, WD., Katch, FI., Katch, VL. Exercise Physiology. Eighth Edition. Baltimore: Wolters Kluwer Health. 2015.

Safarinejad, M., et. al. The effects of intensive, long-term treadmill running on reproductive hormones, hypothalamus–pituitary–testis axis, and semen quality: a randomized controlled study. Journal of Endocrinology. 2008. 200, 259271.


Baked Salmon with Lentils and Lemon Herb Sauce

Baked salmon with lentils and lemon herb sauce


  • 1 cup black lentils
  • 1 cup red quinoa
  • 4 cups chicken or vegetable broth
  • 340 grams salmon
  • 2-3 cups green beans or other vegetables
  • purple sauerkraut

Lemon Herb Sauce:

  • ½ cup olive oil
  • ¼ cup lemon juice
  • 1 clove garlic
  • generous pinch of salt (to taste)
  • quick squeeze of honey or agave (to taste)
  • chopped parsley (optional)


  1. LENTILS AND QUINOA: Preheat the oven to 230 degrees. Rinse the lentils and the quinoa. Place in a large oven safe skillet or casserole with the broth. Bake for 45-50 minutes or until almost fully cooked. Remove and fluff with a fork.
  2. SAUCE: Make the lemon dressing by blending all ingredients in a food processor or just shaking up in a jar. Set about half of the dressing aside.
  3. SALMON: When the lentils and quinoa are done, place the salmon and any other vegetables you want on top of the lentils (skin side down) and drizzle or brush with half of the lemon dressing. Bake for another 10 minutes. Broil for the last 2 minutes. Depending on how thick the salmon is, if it still needs time, just turn off the oven and let it sit in there for a few minutes to finish.
  4. SERVE: When the salmon is fully cooked, serve with reserved sauce and purple sauerkraut.


Some vegetables will cook just fine in 10 minutes in a hot oven, but others won't. If you're using something that's going to require more time like sweet potatoes, I would suggest par-boiling them before sending them to the oven. Veggies that work great - green beans, asparagus, kale, brussels sprouts, cauliflower, mushrooms, peas... etc.

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