Good sleep matters: it isn't just about clocking hours

Why sleep quality and quantity matter

Research from the American Heart Association (AHA) published in the journal Circulation¹ shows that healthy sleep habits - such as consistent bedtimes, getting enough sleep, uninterrupted rest, and overall satisfaction - are linked to a lower risk of stroke, high blood pressure, obesity, and other cardiometabolic conditions such as heart disease and Type 2 diabetes.

No single factor defines sleep health. Instead, several related components help shape your sleep quality and its effect on your health. The key components that affect your sleep, and therefore your health, include:

• Duration - Sleeping for fewer than 7 hours or more than 9 hours can raise the risk of atrial fibrillation, cardiometabolic syndrome, stroke, and heart disease.

• Continuity - frequently waking up or having trouble falling asleep are linked to higher risks of heart attack, high blood pressure, and insulin resistance.

• Timing - there is limited research, but studies indicate that going to bed after midnight is associated with increased risk of obesity and high blood pressure.

• Regularity - inconsistent sleep schedules – such as sleeping-in on weekends - are linked to a 20% higher risk of obesity and a greater risk of typ 2 diabetes.

• Daytime functioning - dozing off during the daytime is linked to heart disease, stroke, and related conditions. It can also be influenced by obesity, diabetes, depression, smoking, and sömnapné.

• Sleep architecture - disruptions in deep (slow-wave) sleep can lead to higher insulin resistance.

• Satisfaction – being unhappy with your sleep quality is associated with higher blood pressure and heart disease.

Drinking alcohol can also affect the quality of your sleep. Whilst drinking can help you fall asleep initially, it disrupts your natural sleep cycle, leading to fragmented and less restful sleep, and frequent awakenings.

The American Heart Association includes sleep duration in its eight metrics for good heart and brain health.

Sleep health is also shaped by external influences. More than 300 studies show that lower socioeconomic status is consistently linked to poorer sleep. People from certain racial and ethnic backgrounds are more likely to have shorter sleep, irregular patterns, and lower satisfaction.

“Everyone’s sleep experience is different, and these differences can contribute to broader health disparities,” says St-Onge.

St-Onge says you should monitor your sleep and adopt best practices just as you would other aspects of your health:

“Some changes in sleep are natural with ageing, but poor or worsening sleep shouldn’t be accepted as inevitable. If you’re struggling to fall or stay asleep, or feel excessively tired during the day, speak with your doctor.”

1. Marie-Pierre St-Onge et al: Multidimensional Sleep Health: Definitions and Implications for Cardiometabolic Health: A Scientific Statement From the American Heart Association