The most common cause of vascular obstruction is a blood clot, also known as a DVT. This type of vascular problem usually occurs in one leg (not both), and leads to swelling of the soft tissues throughout the foot and ankle. The swelling can also extend further up the leg.
The hypothalamus is a part of your brain that controls body temperature. When you exercise, your body temperature increases, causing the hypothalamus to signal the brainstem to further increase your heart rate.
There is a direct correlation between your exercise intensity and the amount of thyroid hormone you produce. In other words, low thyroid levels are associated with low-intensity exercise, and as you increase your intensity level, your thyroid levels increase too. Exercise performed at the anaerobic threshold causes prominent changes in hormone values, and they continued to rise up to 90% of max heart rate [2].