An alcohol consumption affects training performance - Here's how?

Alcohol is not an essential part of the human diet but various alcohols of which the only one quantitative significance of ethanol are consumed by larger part of the world's population. And also alcohol is significant source of energy 7 kilo calories (29 Kilo Joule) per gram of alcohol (Ethanol). Intake of alcohol may impair performance of endurance training. There is some groups of evidence supported that athletes consume more alcohols than non-athletes. 

 Ethanol on an impaired glycogen metabolism:

Re synthesis of glycogen stores in liver and muscle is one of the key goals of athletes after intensive training or competition. Most of the evidence shoes that synthesis of of glycogen is impaired by impaired hepatic glucose output in the presence of even relatively low levels of ethanol. At the same time there seems to be no effect on type 2 muscle fibers. The reduced hepatic glucose output will result in less insulin secretion and thereby ethanol affects the glucose release and glucose uptake into the cells.

Research Findings

"Level of Glycogen storage after exercise depletion and recovery period with different diets"

 From the study, Experts have observed alterations in the carbs(High) and alcohol(Low) intake may have difference in muscle glycogen when compared to high alcohol low carbohydrates diet

Alcohol on Hydration and Thermoregulatory function:

Diuretic action of ethanol is well recognized, an estimation urine production of about 10 ml for each gram of ethanol ingested. But diuretic action was greatly attenuated when the individuals is already hypohydrated induced by exercise in the heat. Alcohol suppress ADH (Anti-Diuretic Hormone) secreted from posterior pituitary gland.

If the drinks contains 4% alcohol tend to delay recovery process by promoting urine loss. Concentrated alcohol solutions will result in net negative fluid balance. Ingestion of large amount of dilute alcohol will result in water diuresis

Why do we need to abstain from alcohol prior to exercise?

The reason because large doses of alcohol before exercise at low ambient temperature results in increased peripheral validations and notable fall in core temperature and fall in blood glucose.

this is clearly and adverse effect of performance. Consuming 2.5ml/kg of alcohol before 3 hours of training will results in increased heat loss

The day after alcohol use:

The day after the drinking session for such activities to be discouraged. Research shows, aerobic performance is decreased with an intake of 10-380 ml of pure alcohol. Anaerobic was unaffected. Negative effect of aerobic performance was apparent at even the smallest dose of alcohol due to dehydration, alterations in glucose metabolism via effects on circulating insulin and glycogen levels, disruption in of cytokine and prostagladins pathways.

During hangover phase also decreases in cardiovascular function (Increased heart rate and reduced left ventricular performance and increased blood pressure)

Chemical breakdown of alcohol:

Ethanol is converted into acetaldehyde, a toxic substance also known as carcinogen with the presence of alcohol dehydrogenase enzymes (ADH), then acetaldehyde further converts into acetate and water with aldehyde dehydrogenase enzyme this process occurs mainly in liver and also in brain, gastrointestinal tract, pancreas. 

Ethanol is either carbohydrate or lipid. Structurally its seems like carbohydrates but it metabolism seems like lipids. consume 10% ethanol from the total energy intake is considered as the moderate level and more than and up to 50% that is meant for alcoholics. Ethanol is absorbed entirely in gastrointestinal tract and transported into the blood stream

Alcohol dehydrogenase enzyme is soluble enzyme functioning in the cytoplasm of the hepatocytes. Its a NAD+ requiring dehydrogenase and it can able to oxidize ethanol to acetaldehyde with the formation of NADH, which is oxidized by the mitochondrial electron transport chain thereby giving rise to ATP formation by oxidative phosphorylation. 

Toxic levels of ethanol is considered to be in the range of 50 to 100 mg/dL 

Alcohol effects on vitamin deficiency:

Excess alcohol metabolism is associated with deficiency of vitamin-A. Reason because ethanol inhibits the hepatic conversion of retinol into retinal, which is required for synthesis of  photo pigments used in the vision. It is necessary for alcoholics to intake higher dietary vitamins in order to maintain normal hepatocyte concentration

Alcohol in moderation: A Bright-spot

So far we've seen the negative impacts of alcoholism on metabolism and nutrition. Many studies have suggested that alcohol consumed in moderation may have beneficial effects and it improves plasma lipid profile (Increases High density Lipoprotein levels in serum, Decrease serum lipoprotein) thereby it is slowing down the athrogenic process and reduce the risks of cardiovascular diseases.

In the bottom line,

The mode of alcohol consumption in the human experimental studies has either acute (single dose) or chronic (Repeated dose over a period) can decrease the use of glucose and amino acids by skeletal muscle.subsequently it reduces the training performance and chronic use of citrate synthase activity and decreased muscle cross sectional area in type I,IIa,IIb. Ethanol attenuate hepatic mitochondria and accelerates ethanol metabolism by the liver by inhibiting other metabolism.