How poor sleep and high stress levels make you less healthy
A cardiologist and data science expert break down how sleep and stress affect your heart rate variability, which has implications for your overall health.
What you need to know about HRV, sleep and stress.
Living through a pandemic has taken a toll on your stress levels and sleep quality, which not only makes you feel run down and tired, but it can also having lasting negative impacts on your health. Poor sleep and high levels of stress can lower your heart rate variability, which is gaining attention as a key health stat we should all be tracking.
"Heart rate variability is exactly what it says -- it's the variation in the timing of the heartbeat beat to beat." says Dr. Sameer Mehta, a cardiologist at Denver Heart. HRV is measured in a number of different ways, but popular fitness and sleep trackers like Whoop, Oura, and Apple Watch are among the easiest ways to track it.
Why should you care about HRV? For starters, "there's a variety of data that shows people with lower heart rate variability do worse in a variety of ways. Their fitness performance is worse. They have increased adverse health outcomes, including cardiovascular deaths, myocardial infarctions (heart attacks) and strokes," says Dr. Mehta.
HRV can tell you a lot about your sleep, stress and overall health, making it an important metric to understand. That said, lots of things can affect your HRV numbers, including your workouts, your diet and whether or not you're sick. For that reason, understanding how sleep and stress can affect HRV can help you prevent potential health issues that are linked to poor sleep, and mismanaged or chronic stress.
What influences HRV?
HRV is closely connected to your nervous system, which involves a lot of other important health factors, like sleep and stress. To understand HRV a bit better, you need to look at how the nervous system functions, since factors that affect the nervous system also affect HRV.
How the nervous system works
The autonomic nervous system consists of the sympathetic and the parasympathetic systems. The sympathetic side takes over, "when we're under physical duress, increased stress, depressed, we don't sleep as well or have increased alcohol intake. Our sympathetic nervous system becomes overactive, which then decreases our heart rate variability," explain Dr. Mehta.
The parasympathetic system is activated when you're more relaxed, well rested, in shape and in overall better health (physically and mentally.) "And that is when we see increased heart rate variability," says Dr, Mehta.
Low HRV can be caused by these factors, according to Dr. Mehta:
- Increased stress
- Poor sleep
- Depression
- Poor diet
- Substance abuse
High HRV is linked to the following factors, according to Dr. Mehta:
- Being physically fit
- Good blood pressure
- Good diet
- Adequate sleep
- Decreasing alcohol and substance use
How sleep, stress and HRV are linked
Since HRV is influenced by sleep, it makes sense that getting enough sleep each night will help you reach a higher HRV. But it's not just about the number of hours -- your sleep quality matters, too.
"When we go into deep sleep, which is good sleep and more restful sleep, that's when we see increased heart rate variability," says Dr. Mehta. Conversely, when you don't sleep enough, or when your sleep is fragmented or disrupted throughout the night, your HRV can suffer too.
The sleep and stress connection
When you're stressed, it's harder to fall asleep and stay asleep, which can lead to a vicious cycle that leaves you feeling stressed and tired all the time.
"If you're not getting the sleep you need, you're definitely going to see lower HRV and then sort of lower capacity emotionally, which can lead to stress," explains Emily Capodilupo, VP of Data Science and Research at Whoop (a fitness wearable that tracks HRV). "And our bodies just do everything poorly when we're sleep deprived, including regulating emotions and handling things," says Capodilupo. It's all part of a stress-no-sleep domino effect that will not do any favors for your health or HRV.
Dr. Mehta adds that figuring out how to break out of the stress sleep cycle can start with better sleep and stress hygiene habits. "Restful sleep or deep sleep correlates highly with mental hygiene. So stress management, which includes eliminating stress and managing stress," he says. Dr. Mehta adds that one thing many people use to cope with stress is alcohol, which you should avoid as a coping tool since it can affect your sleep quality, and in turn, your HRV.
Addressing poor sleep and high or chronic stress levels is key to maintaining high HRV and in turn, good overall health. If you struggle from insomnia, sleep apnea, or have trouble falling or staying asleep, see your doctor and talk to them about getting checked out for any underlying health problems or if you need to seek testing and treatment for sleep disorders. About 30% of people have trouble sleeping, and 10% of those people get diagnosed with insomnia, Dr. Deirdre Conroy, clinical director of the Behavioral Sleep Medicine Clinic at the Michigan Medicine Sleep Disorders Centers, told CNET.
If you suspect stress is keeping you up at night or interfering with your health in general, consider trying meditation, which can help you reduce stress and increase mindfulness. If you're having a hard time coping with stress, seeing a therapist is also helpful, and it's easier than ever to find a therapist that can help you online. Exercise can also help reduce stress, and you can try restorative exercises like yoga or stretching if you're not feeling up to a more strenuous workout. Addressing sleep issues and finding healthy ways to cope with stress will help you maintain a higher HRV, which will set you up for a healthier future in the long run.