Testosterone levels decrease with age. This is perfectly natural and happens to all men as they get older.
Don’t panic, though – the decline is gradual at less than 2% a year from around the age of 30.15
Type II diabetes has shown to be closely associated with lower testosterone levels in clinical studies.16
According to NHS Diabetes, 16% of males with type 2 diabetes have lower than normal levels of testosterone and an additional 24% have testosterone levels close to the border of low levels.17
Studies have concluded that an elevated BMI is associated with reduced total testosterone levels in men.18
There is a particular link between low testosterone and abdominal obesity.19
This is the fat which accumulates around a man’s waist and can include both visceral fat (fat deep inside the abdominal cavity) and subcutaneous fat (the soft fat we see just under the skin).
Testosterone builds at night, during REM sleep. Therefore, poor quality sleep reduces testosterone levels.20
One study on young, healthy men restricted their sleep from 8 hours 55 minutes per night to 4 hours 48 minutes per night.
Testosterone levels in the men were found to be much lower after sleep restriction than after the restful night’s sleep.21
Testosterone levels are known to reduce when a man is under stress.
This includes both psychological stress such as fear and anxiety and physical and actual stress such as pain.22
Further, research has also found that anticipatory stress – such as worrying about a future event – can also reduce testosterone levels in men.23