Hypothyroidism is a medical condition marked by an underactive thyroid gland. The thyroid gland produces thyroid hormones, which affect many physiological functions, including muscle, liver and cardiovascular function. When thyroid hormone levels are insufficient, impairments of these functions may occur, leading to such possible symptoms as muscle damage and high cholesterol.
Hypothyroidism and Muscle Damage
Hypothyroidism can weaken muscles, such as the diaphragm, causing respiratory difficulties and a reduced oxygen supply. Joint and muscle aches and pains are common, as is fatigue. Additionally, low thyroid hormone levels cause muscle fibers to switch types from fast- to slow-twitch fibers. Because of these factors, and the low blood sugar, blood oxygen, blood pressure and heart rate typical with symptomatic hypothyroidism, muscles do not respond well to exercise and are more susceptible to damage from injury or heavy use and activity, including strength training exercises. Related hypothyroidism symptoms that may affect muscle strength and resistance to damage include poor focus and concentration, weight gain, and poor exercise tolerance.
Hypothyroidism and Cholesterol
As reported in the January 1994 "Medical Clinics of North America," next to diet, hypothyroidism is the leading secondary cause of hyperlipidemia, or high cholesterol. With thyroid hormone levels lowered, the liver cannot function properly and therefore starts producing an excess of fatty acids, triglycerides and cholesterol. This can lead to an increased risk of heart disease. If medication for high cholesterol is failing to correct the problem, it may be due to a deeper underlying problem of hypothyroidism that isn't being addressed. If you have concerns about your cholesterol levels or have been diagnosed with high cholesterol, ask your doctor to test your thyroid hormone levels as well to see if hypothyroidism may be a factor.
Muscle Damage and Cholesterol
Statin medications taken to treat high cholesterol levels may cause a reduction in muscle tone and related muscle pain and weakness. A potential for muscle damage is also present with statin drugs, either as a precursor to or a consequence of these muscle symptoms. The higher the potency of the statin drug, the higher the risk of these side effects.
Exercise
While a sedentary lifestyle may be a risk factor for hypothyroidism, high LDL or bad cholesterol levels and poor muscle tone, and a resistance to and low tolerance for exercise may be a consequence of these conditions, increased exercise may help remedy all of them as well. Regular exercise can help improve muscle tone and repair and protect against future muscle damage. It can also help raise HDL or good cholesterol levels.
References
- ProQuest; Thyroid Hormone Disorders; Jennifer A. Phillips; May 2001
- "FASEB Journal"; Statin-Induced Muscle Damage and Atrogin-1 Induction is the Result of a Geranylgeranylation Defect; P. Cao; Sep 2009
- MayoClinic.com; Hypothyroidism (Underactive Thyroid): Complications; June 2010
- University of Maryland Medical Center; Hypothyroidism; Harvey Simon; May 2009
- "Medical Clinics of North America"; Secondary Causes of Hyperlipidemia; N.J. Stone; Jan 1994
