Recovery Tip: Alcohol Can Tank HRV, Resting Heart Rate, and Sleep

Published July 25, 2022 02:49PM

It’s no secret that alcohol inhibits overall health, but for triathletes, the risks are even more adverse. Drinking alcohol negatively affects your heart rate variability (or HRV) and heart rate, hinders sleep, can lower testosterone, impair balance and coordination, decrease muscular strength, and impact bone health—which increases the risk of sports-related injuries. Simply put: you shouldn’t plan to just “sweat it out” post-drinking.

How long does it take an athlete to recover from drinking alcohol?

Varying amounts or types of alcohol tend to affect people differently. But generally speaking, the more that’s consumed, the greater the psychological and physiological consequences. It takes the liver at least one hour to remove each unit of alcohol from the body, and the liver may struggle to remove all the alcohol overnight.

Alcohol affects the body in many ways, including excessive thirst as a result of alcohol’s diuretic effect, and diarrhea and indigestion as the alcohol wreaks havoc on the digestive system and increases stomach acid production.

Alcohol’s effect on heart rate and HRV

Heart rate and heart rate variability (HRV) are two useful metrics for athletes to monitor in order to get a baseline of nervous system activity and gauge how the body is capable of adapting to different situations. Consuming alcohol is shown to cause HRV to drop, and resting heart rate to rise. A normal resting heart rate for adults is between 60 and 100 beats per minute, and researchers in one study found that consuming just one standard drink elevated participants’ heart rates by five beats per minute. Another analysis by the fitness tracking company WHOOP reported that respondents’ HRV dropped by an average of 7 milliseconds and their resting heart rate increased by an average of three beats per minute after one drink.

“Greater alcohol consumption is associated with more pronounced increases in heart rate,” said UK-based exercise physiologist Tom Cowan. “This may be amplified if the alcohol is accompanied by a mixer, which contains caffeine such as an energy drink or in a cocktail like an Espresso Martini, as caffeine also increases heart rate.”

Why is monitoring HRV and heart rate important?

Resting heart rate has long been a reliable tool for athletes to monitor, but HRV has now become increasingly popular as a recovery and training metric—both in general fitness trackers and for athletes. An HRV device measures the interval between each of your heart beats, in milliseconds (m/s), over a specific period of time. More variability between beats gives you a higher score—and, in general, means you’re fitter and more recovered and ready to go. HRV tends to drop when a person is tired, stressed, sick, not recovered from a previous day’s workout, or after a night of drinking.

“A higher HRV generally equals better fitness,” said Harry Glorikian, healthcare expert and author of The Future You: How Artificial Intelligence Can Help You Get Healthier, Stress Less, and Live Longer. But it’s important for each person to establish an individual baseline before analyzing changes in their HRV, he noted, because it’s a highly individualized metric. What is normal for you might not be normal for someone else. “The first time I saw my HRV numbers, I started to look for ways to compare it to others. What I quickly found was that my HRV was specific to me and that changes that I made in my life affected my HRV and those changes do not apply universally to others.” His takeaway? Focus on implementing your own changes when it comes to diet and exercise, and watch as your HRV increases and your energy levels soar.

Start by establishing a baseline HRV and resting heart rate every morning for a least one to two weeks, using your fitness tracker or app. Then you can note differences.

It’s also important to know that while, in general, higher HRV correlates with better fitness and recovery, and lower resting heart rate tends to mean an individual is more recovered and rested, this is not always the case. There can be individual circumstances that go against this general rule and extremely fit athletes can have inverse effects. For instance, the resting heart rate could become suppressed from extreme fatigue and overtraining.

“Once you start to utilize this measure, keep in mind that training is not the sole influencer of this metric. Work stress, poor sleep, stressful family life, poor nutrition, and more can negatively affect HRV,” he said.

Why alcohol can impact sleep—and HRV

Poor sleep, as well as stress (physical or psychological), can reduce HRV. A restful night’s sleep helps the body to restore itself, repair cells and tissue, and prepare again for optimal performance. So what happens after a few evening glasses of wine?

“Alcohol disrupts sleep cycles and since it is a diuretic, it may lead to you waking up to go to the toilet frequently during the night,” said Cowan. “This leads to a reduction in sleep quality, has negative impacts on recovery, and can result in lower heart rate variability. Alcohol is also often consumed at social gatherings and parties that extend into the night or the early hours of the morning, likely affecting sleep duration too, leading to inadequate recovery.”

“A chronic lack of sleep can increase blood pressure, which when high, known as hypertension, is a risk factor for cardiovascular disease. Two further cardiovascular disease risk factors; being overweight and having elevated cholesterol are also both more likely with excessive and prolonged alcohol intake,” Cowan adds. “Poor sleep can affect immune function, leaving the individual more susceptible to infection and illness.”

Another issue that can affect performance is that poor sleep impacts the hormones which control appetite (leptin and ghrelin). As such, an imbalance can lead to overeating, cravings, and even additional poor food choices.

“Exercise and sleep have an important two-way relationship: sleep improves our energy levels which help us to be physically active, whereas a lack of restorative sleep can leave us feeling tired and groggy and less likely to perform the next day’s training session effectively—or to skip it entirely. On the other hand, performing exercise and being physically active can help to improve sleep,” he said. But alcohol’s effects aren’t limited to sleep

The physiological risks of alcohol consumption for athletes

Alcohol can lead to numerous problems when it’s mixed in with a heavy training plan. Plus, it’s not just the recovery factors—alcohol can also slow down reaction speed, concentration, and decision making, all of which are crucial in sport.

“As alcohol can affect balance and coordination, it may increase the risk of injuries from falls and accidents and affect an athlete’s ability to compete or train,” Cowan warns. “Alcohol is a diuretic and can lead to dehydration if fluids aren’t replenished. Dehydration can negatively affect exercise performance by impairing cognitive performance and reducing blood volume, which increases heart rate and affects thermoregulation, causing body temperature to rise. The risk of dehydration is heightened when exercising, as it is likely that the athlete will also be losing further fluid from the body as sweat and even more so if exercising in a hot climate.”

All of those things are bad for optimal performance, but he continues: Heavy consumption of alcohol can also lead to lower testosterone levels. Testosterone has anabolic effects and is important for the maintenance and development of muscle mass and strength. Studies have shown alcohol intake following exercise can result in reduced rates of muscle protein synthesis, and therefore negatively impact the physiological adaptation to exercise.

“Athletes should closely monitor and limit their alcohol intake as much as possible, and ideally refrain from drinking to avoid the harmful physiological and psychological consequences,” Cowan advises. “This is perhaps even more pertinent during an intense training schedule.”