Exercise physiology loss of integrity to the blood brain barrier. Hyperthermia also can lower cerebral blood flow, and raise brain temperature. Researchers once attributed fatigue to a build-up of lactic acid in muscles. However, this is no longer believed. Rather, lactate may stop muscle fatigue by keeping muscles fully responding to nerve signals. The available oxygen and energy supply, and disturbances of muscle ion homeostasis are the main factor determining exercise performance, at least during brief very intense exercise. Each muscle contraction involves an action potential that activates voltage sensors, and so releases Ca ions from the muscle fibre’s sarcoplasmic reticulum. The
Abdominal exercise Abdominal exercise Abdominal exercises are those that affect the abdominal muscles (colloquially known as the stomach muscles or "abs"). Abdominal exercises are useful for building the abdominal muscles. This is useful for improving performance with certain sports, back pain, and for withstanding abdominal impacts (e.g., taking punches). According to a 2011 study, abdominal muscle exercises are known to increase the strength and endurance of the abdominal muscles. It has been highly disputed whether or not abdominal exercises have any reducing effect on abdominal fat. The aforementioned 2011 study found that abdominal exercise does not reduce abdominal fat; to achieve that,