Testosterone is a hormone that plays a crucial role in maintaining overall health and athletic performance. It is responsible for muscle mass, strength, bone density, and sex drive in both men and women. However, as individuals age, their testosterone levels begin to decline, which can have significant health and performance implications. This article will highlight the importance of monitoring testosterone levels for sports performance and describe how these numbers decline after a certain age. It will also provide baseline values for healthy males and females for each decade of their lives and discuss the health and sports performance implications of low testosterone levels. Finally, it will provide interventions that can be put in place from a dietary, exercise, supplemental, and pharmacological perspective.
Decline in Testosterone Levels
Testosterone levels decline as individuals age. According to a study published in The Journal of Clinical Endocrinology and Metabolism, testosterone levels decrease by approximately 1.6% per year in men after the age of 30 (1). This decline is more significant in older men, with a 20% decline in testosterone levels between the ages of 50 and 70. Similarly, women experience a decline in testosterone levels after menopause, which can have significant health and performance implications.
Baseline Values for Healthy Males and Females
Baseline values for healthy males and females vary by age. According to a study published in the International Journal of Sports Medicine, the following are considered normal testosterone levels in healthy males by decade of life (2):
20-29 years: 617 ng/dL
30-39 years: 669 ng/dL
40-49 years: 606 ng/dL
50-59 years: 562 ng/dL
60-69 years: 524 ng/dL
70-79 years: 471 ng/dL
For healthy females, normal testosterone levels are much lower, with a range of 15-70 ng/dL, depending on age and menstrual cycle phase (3).
Health and Sports Performance Implications of Low Testosterone Levels
Low testosterone levels can have significant health and sports performance implications. In men, low testosterone levels can lead to decreased muscle mass and strength, decreased bone density, increased fat mass, decreased sex drive, and erectile dysfunction (4). In women, low testosterone levels can lead to decreased muscle mass, decreased bone density, increased fat mass, and decreased sex drive (5).
In addition to the health implications, low testosterone levels can also impact athletic performance. According to a study published in the Journal of Strength and Conditioning Research, athletes with low testosterone levels have decreased muscle strength and power output, decreased aerobic capacity, and decreased endurance (6).
Interventions for Low Testosterone Levels
There are several interventions that can be put in place to address low testosterone levels, including dietary, exercise, supplemental, and pharmacological interventions.
- Dietary Interventions: A diet that is high in protein, healthy fats, and complex carbohydrates can help increase testosterone levels. Foods that are rich in zinc, such as oysters, beef, and poultry, can also help increase testosterone levels (7).
- Exercise Interventions: Resistance training, in particular, has been shown to increase testosterone levels in both men and women (8). High-intensity interval training (HIIT) and sprint interval training (SIT) have also been shown to increase testosterone levels in men (9).
- Supplemental Interventions: Supplements such as vitamin D, D-aspartic acid, and ashwagandha have been shown to increase testosterone levels in men (10). However, more research is needed to determine their effectiveness in women.
- Pharmacological Interventions:
- Testosterone replacement therapy (TRT): TRT involves the administration of testosterone to replace the missing hormone. This can be done through various methods such as injections, gels, patches, and pellets.
- Selective estrogen receptor modulators (SERMs): SERMs are drugs that block the effects of estrogen in certain tissues, which can help to increase testosterone levels.
- Aromatase inhibitors: Aromatase inhibitors are drugs that block the conversion of testosterone to estrogen, which can help to increase testosterone levels.
- Human chorionic gonadotropin (hCG): hCG is a hormone that can stimulate the production of testosterone in the testicles.
- Clomiphene citrate: Clomiphene citrate is a drug that can stimulate the production of testosterone by the testicles.
It is important to note that these pharmacological interventions should only be used under the guidance and supervision of a healthcare professional. They may not be appropriate or safe for everyone and can have potential side effects.