The effects of alcohol on performance and recovery in muscle tissue

16th December 2016

Alcohol affects the central nervous system and muscle function

If you have ever consumed more than a moderate amount of alcohol, you may be familiar with some of the effects that alcohol can have on the central nervous system, such as loss of motor control and balance. What you may not know is how acute (heavy) ethanol consumption affects muscle contraction and causes muscle weakness and soreness that can last for several days post drinking [1]. When you decide to move your body, an electric signal must travel from your brain along your central nervous system (CNS) to your peripheral muscle and cause a contraction – this is called excitation-contraction coupling. Alcohol reduces a muscles ability to respond to signals from the CNC in a couple of ways.

Firstly, ethanol dampens the signal strength as it travels through the membrane of the sarcolemma (skeletal muscle envelope) [1]. For example, if you need to lift a 5kg dumbbell, you need to create many electrical signals with your brain which will stimulate many muscle fibres, in comparison to the moderate amount of muscle stimulation needed to lift a pencil. When you have consumed alcohol and send attempt to send the same electrical signals to your arm to lift the 5kg dumbbell, the muscle cells will not receive the full strength of the signal, and you will feel muscle weakness. Secondly, ethanol inhibits the voltage gated calcium ion channels which are required to convert the electrical signal from your brain in to the actual cellular contraction of the muscle. Furthermore, ethanol can reduce the number of calcium ions present with the muscle, which can cause muscle weakness long after you have stopped drinking [1]. Overall, the effect of acute ethanol consumption on muscle function is to cause fatigue or weakness that can be felt during intoxication and up to two days afterward.  

Additionally, acute ethanol consumption will prolong muscle recovery and repair by interfering with the levels of particular hormones in your bloodstream. These hormones (cortisol, androgens, and growth hormone) are responsible for stimulating repair within the muscle cells, and when they are blocked by alcohol consumption recovery is delayed [2]. You know that sore feeling you get in your muscles after conditioning class? Those are micro-tears in your muscle fibres that are necessary for growth, but the repair process will be hindered by ethanol, meaning the feeling will probably last much longer if you consume excess quantities of ethanol.   

 

Other indirect effects of alcohol on muscle function

Hopefully you have never experienced your body’s final mechanism to inhibit you from consuming more alcohol – passing out. While it might seem that initially you are sleeping hard, unfortunately you are not. Acute alcohol consumption greatly reduces both the quality and quantity of sleep you will experience after drinking. In the first half of the night, alcohol will reduce waking, as well as the amount of rapid eye movement (REM) sleep, which is what induces the ‘coma like’ sleep you may have experienced post drinking [3]. REM sleep is a requirement for your physiological wellbeing, and plays a major role in the brains ability to remember, learn new skills, and to allow for brain plasticity [4]. When you learn a new pole move, it is not just the physical strength and flexibility that you need to master, but it is also something that your brain must remember how to do, and how to properly execute.

In the second half of the night after consuming alcohol, sleep is interrupted by frequent waking, which again interrupts the cycling of REM with non-REM sleep. While the reasons why we need sleep to survive are still unknown, some of the vital processes that occur during sleep have been well documented. Sleep restores the immune and endocrine systems, which are your defence against infection; it detoxifies cells allowing them to eliminate wastes and grow; and finally sleep restores the nervous system [3]. A loss of sleep caused by alcohol consumption can therefore result in increased errors, decreased muscle power, increased anger and irritability, and a reduction on focus and patients [3], all of which will greatly reduce your ability to grow as an athlete.

Alcohol can also indirectly affect muscles through an increased susceptibility to injuries, reduced healing, as well as infection rate. As previously discussed, when intoxicated, you have reduced skeletal muscle control. This increases the risk of trauma, as well as trauma severity [5]. When injured during or directly after intoxication, the body is less able to heal as growth hormones are inhibited. Further, the body will circulate very high levels of pro-inflammatory mediators which can damage neighbouring tissues. To top it off, infection rate and severity is much greater as the body’s immune system is impaired [1]. Just when you thought it couldn’t get worse, alcohol also accelerates disuse muscle atrophy, which means while you take time off to recover, your muscles will degenerate at a faster rate! These complications mean that an injury that may have never happened in the first place results in a long, drawn out injury that requires extra time off training, and results in an increased rate of muscle loss…Yuck!

Lastly, excess alcohol consumption negatively affects nutrient uptake both within the gastrointestinal tract [6] and again within the muscle cells [7]. When alcohol is consumed, it can directly irritates the mucus membranes of the gastrointestinal tract, causing nausea and vomiting while in the stomach, haemorrhaging and inflammation in the small intestine, and diarrhoea while in the large intestine. All of these effects cause severe dehydration, electrolyte loss, and impaired uptake of vitamins and nutrients [6] which will deprive an athlete of everything they need to grow and repair. Once in the bloodstream, alcohol can further affect the nutrients muscle cells receive. Muscles rely on glycogen as their primary energy source, and acute alcohol consumption reduces muscle glycogen uptake and storage [7]. Without a constant energy source, muscle cells inhibit repair and any other excess energy consuming activities.

Summary and recommendation for athletes who consume alcohol

Acute alcohol consumption has been shown to have many negative effects on an athlete’s performance, recovery, and growth. On a molecular level, it reduces muscle strength, increases muscle fatigue, and prolongs muscle repair. Alcohol can also reduce your quality of sleep which can further delay muscle growth and repair, as well as affect your training in the following days, making you weak, frustrated and exhausted.

Don’t be too disheartened though, through this article you would have noticed that it was always acute/excess alcohol consumption that lead to negative results. So what is excess alcohol consumption? And how can you keep enjoying alcohol without hindering your pole-ability.  Keeping to the “one standard drink per hour” is not necessarily a one size fits all standard, but it is a good starting point. If you want to reduce any damage to your muscles and pole dancing skills, you should stay below 1 g of ethanol per kg of body weight. For example I weigh 60 kg, therefore I can safely consume 60 mL of ethanol. That doesn’t mean I can only consume 60 mL of my favourite red wine! Remember, wine is only approximately 15% (0.15) ethanol. I can safely consume approximately 400 mL of red wine. A simple calculation you can do to determine the safe quantity of your favourite drink

Your body weight in kg / the percentage of alcohol you are consuming = the number of mL you can consume of that alcoholic beverage

In the above example 60/.15 = 400

 

 

1.            Barnes, M.J., T. Mundel, and S.R. Stannard, The effects of acute alcohol consumption and eccentric muscle damage on neuromuscular function. Appl Physiol Nutr Metab, 2012. 37(1): p. 63-71.

2.            Haugvad, A., et al., Ethanol does not delay muscle recovery but decreases testosterone/cortisol ratio. Med Sci Sports Exerc, 2014. 46(11): p. 2175-83.

3.            Halson, S.L., Nutrition, sleep and recovery. European Journal of Sport Science, 2008. 8(2): p. 119-126.

4.            Smith, C.T., M.R. Nixon, and R.S. Nader, Posttraining increases in REM sleep intensity implicate REM sleep in memory processing and provide a biological marker of learning potential. Learning & Memory, 2004. 11(6): p. 714-719.

5.            Vargas, R. and C.H. Lang, Alcohol accelerates loss of muscle and impairs recovery of muscle mass resulting from disuse atrophy. Alcohol Clin Exp Res, 2008. 32(1): p. 128-37.

6.            Chiba, T. and S.F. Phillips, Alcohol-related diarrhea. Addiction Biology, 2000. 5(2): p. 117-125.

7.            Vella, L.D. and D. Cameron-Smith, Alcohol, athletic performance and recovery. Nutrients, 2010. 2(8): p. 781-9.