As men pass the age of 40 their natural testosterone production is well in decline. As our testosterone decreases our estrogen increases.

the enzyme aromatase converts our testosterone to the estrogen hormone estradiol. As we age, this reaction increases.
This hormonal imbalance — if too steep — can cause health concerns such as gynecomastia (breasts on men), fatigue, prostate issues, type 2 diabetes, infertility and bone density loss. Although it is inevitable that testosterone production dips, there are ways to mitigate the loss. A common path nowadays is to receive Testosterone Replacement Therapy (TRT) but as we previously reported, there are health risks associated with this method.
Nutrition is a big part of the battle. Avoiding excess sugars and simple carbs goes a long way to help. Obesity is also a driver of low testosterone as is over training and too much stress. When we are stressed we produce a lot of cortisol (the “stress” hormone). In order to produce large amounts of cortisol (which occurs when we are greatly stressed) we need progesterone. If we are using a good dose of progesterone to make cortisol, it is less available for its other important job: balancing testosterone to estrogen concentrations. Which can lead to too much estrogen floating around.
Heavy Weights
As studies continue to show, when men (and women) lift heavy weights (enough to limit repetitions to 10 or less) the body boosts its testosterone activity. One single intense training session can increase your Growth Hormone and testosterone levels and one study on 55 to 70 years olds showed that a single exercise session can release a wave of Growth Hormone into your blood stream that is 18 times higher than the resting levels. This means that regular exercise bouts will keep your blood supply loaded with considerable Growth Hormones and higher than normal testosterone. All triggered by a perfectly natural method with zero negative side effects.
Regularly stressing the bone structure is also one of the best ways to continually trigger your body’s natural bone construction activity. Which will greatly help stave off osteoporosis. The “dopamine drop” post exercise increases mood and decreases stress. Not to mention that a regularly trained body is stronger, more resilient to other activities and looks better.
So if you are interested in beginning a weight training regimen, especially a heavy one, make sure to be instructed on proper lifting technique first. You don’t want to be sidelined by unnecessary injury. Once you are safely able to handle weights make sure to pick a weight that you can safely lift but cannot break the 10 repetition barrier. You will want to hit “muscle failure” (i.e.: the inability to lift anymore) before or at the 10 rep mark. You should do this for 3 to 4 sets for each muscle group. You will spread out your workouts over a week period, doing each group only once per week. Intense non-weight exercises such as sprinting or stair climbing are also triggers for testosterone. Feel free to change up your routine and get creative.
Press on!