With improved blood circulation to the scalp hair follicles will get a good supply of oxygen and nutrients from our diet. Good blood circulation also helps in distributing natural sebum evenly across the scalp, leading to good hair growth. This will result in healthier hair with more volume.hen blood flow in the scalp area is less than the normal, it will not receive the essential nutrients required for healthy hair growth. This will ultimately result in various hair related problems. But when you exercise your stress level decreases, which stimulates hair growth.
Twitching in the left thumb may also indicate an overdose of caffeine, stimulants or amphetamines or a drug side effect to estrogen, corticosteroids or diuretics, adds MedlinePlus. Diet is also a cause of left thumb twitching, especially when an individual fails to consume a balanced diet. When the body is unable to fight off ailments, such as an autoimmune disorder, twitching is often a side effect.
Quick Answer. Muscle contractions or twitching within a muscle group powered by a single motor nerve fiber cause a twitch within the left thumb, according to MedlinePlus. Autoimmune disorders, exercise, stress, nutrient deficiencies, a lack of sleep and side effects of medication can cause twitching.