What is optimal heart health? Is it normal heart arteries on cardiac catheterization? Is it the ability to run a marathon? Is it playing a round of golf and walking the course? Is it being able to do moderate exercise without shortness of breath? There are many different and unique perspectives on this question. The American Heart Association’s (AHA) perspective defines optimal heart health using eight variables dubbed “Life’s Essential Eight”.
The AHA initially defined seven variables for optimal heart health in 2010. After 12 years and lots of subsequent research, the AHA updated these seven parameters and added a new one this summer. Here is an update to the original seven with a deep dive into the eighth.
Diet- this was updated to encourage everyone to follow one of the known heart healthy diets; DASH (Dietary Approach to Stop Hypertension) or a Mediterranean Diet.
Physical Activity- no change was made. The optimal level of activity is still 150 minutes per week of moderate physical activity or 75 minutes per week of vigorous exercise.
Nicotine exposure- updated to discourage the use of e-cigarettes (vaping) and to reduce exposure to second hand smoke.
Body Mass Index(BMI) – BMI is body weight divided by height and is a measure of overweight or obesity (A BMI calculator may be found here: https://www.calculator.net/bmi-calculator.html). There was no change to the ideal BMI: between 18 and 25 kg/m2.
Lipids- the updated metric for blood lipids is non-HDL cholesterol (total cholesterol minus HDL). The ideal non-HDL cholesterol for optimal heart health is < 130 mg/dl.
Blood sugar- optimal levels for non-diabetic patients are a fasting blood sugar < 100 mg/dl or Hemoglobin A1C < 5.7%.
Blood pressure- the optimal blood pressure is less than 120/80 mmHg; 130/80 and above is considered hypertension.
The new variable is sleep duration. According the AHA, the ideal duration of sleep for optimal heart health is between seven and nine hours per night. The importance of sleep on overall health has been well documented and known for years. Poor sleep can lead to irritability, anxiety, reduced cognitive performance (including loss of concentration and poor decision making), Alzheimer’s disease and increased risk for obesity, diabetes, heart attack, stroke, hypertension, atrial fibrillation and cancer. Several recent studies outline the risks of not getting a good night’s sleep. A study from the US (6,820 people, mean age 53) looked at various measures of sleep health. Those with poor sleep health had a 54% increased risk for cardiovascular disease. In another study of young healthy people, sleeping only four hours per night added extra weight and specifically added “belly fat”, which has an increased risk for heart disease. The association between sleep and metabolic disease was shown again in a study in women. Sleeping less than 7 hours per night altered glucose (blood sugar) metabolism, leading to diabetes and hypertension. Since sleep is so important, let’s tackle some pressing questions about sleep such as the optimal sleep duration, the best time to go to bed, melatonin and sleep trackers.
What is the optimal amount of sleep? There seems to be a “right” amount of sleep, at least as far as cognitive function is concerned as demonstrated in two recent studies. One study of elderly patients showed dramatic decline in brain function for those who slept less than 4.5 hours or more than 6.5 hours per night. In patients who slept less than 6 hours per night, there was a greater burden of amyloid in the nervous system, a marker for Alzheimer’s disease. Another study from the United Kingdom (500,00 patients, 38-73 years) showed that seven hours of sleep per night was optimal for cognitive performance. Therefore, seven hours of sleep seems to be the sweet spot for optimal health for middle aged and elderly people (children and adolescents need more sleep). Now that we know the optimal amount of sleep, is there an optimal time for bed? An interesting study (88,000 patients, average age 61) answers the question. Researchers found that going to sleep before 10 PM or after midnight increased the risk for heart disease. Those who went to sleep between 11 and 11:59 PM had a 12% higher risk for heart disease and those who hit the sack before 10 PM or after 12 AM had a 24% higher risk. The people who went to bed between 10 PM and 10:59 PM had the lowest risk for heart disease in the study; thus defining the optimal time for bed. In this study, timing of sleep was actually more important then duration of sleep.
If there is difficulty falling asleep and getting the recommended amount of sleep, does melatonin help? Melatonin is a hormone produced by the brain. As darkness falls, the brain senses that it is nighttime and releases melatonin. The elevated levels of melatonin help us fall asleep and stay asleep. As dawn breaks, melatonin levels go down and we wake up. Can over the counter melatonin help people who have trouble falling asleep (insomnia)? Melatonin has been available for quite some time and is felt to be safe, but no formal studies have been done. Over the counter melatonin is not benign. It has effects on body temperature, blood sugar and blood vessel tone. In addition, since it is not regulated by the FDA, melatonin doses vary widely. The American Academy of Sleep Medicine is currently reviewing the safety and efficacy data of melatonin. Until the review is complete, they recommend that it not be used for insomnia.
Are there devices that can help track sleep? There are a variety of sleep tracking devices that fall into two broad categories: devices put under a mattress or pillow and wearable devices. The devices may help to tell you when you went to sleep and your total sleep time. However, no device can diagnose sleep apnea (stopping breathing). In addition, when compared to a formal sleep study (the gold standard for sleep), no device can accurately measure sleep quality. In addition, no sleep tracker or sleep app is endorsed for use by national sleep academies or sleep specialists.
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