Hypertension has many links to lifestyle which generally revolve around diet and exercise. But new research from Australia shows the chance for high blood pressure increases dramatically for every hour of sleep lost or for major shifts in regular sleep patterns, especially among overweight, middle-aged men.

Flinders University scientists conducted a large-scale, extended study into how variable sleep patterns affect blood pressure. They published their findings in the journal Hypertension.

Data from more than 12,000 adults totaling more than 2 million nights of sleep were analyzed. The participants were mostly male and somewhat overweight according to the BMI scale. They all slept in their own homes which were equipped with under-mattress sensors and remote blood pressure monitoring equipment.

The study lasted nine months and each participant had their blood pressure recorded 30 separate times.

Researchers found a strong tie between elevated blood pressure readings and irregular sleep times and durations. That led them to conclude there needs to be public awareness of the link between circadian cycles and hypertension.

"Not only should we monitor the amount of sleep, but we should also keep our resting schedule as regular as possible," said researcher Dr. Hannah Scott.

Those who regularly varied their nightly bedtimes by more than 30 minutes faced an increase in hypertension risk by 32 percent. Inadequate sleep as defined by less than six hours, and even more than nine hours of sleep were also associated with increased blood pressure.

"However, this study also shows that night-to-night variation in sleep timing and duration can have a similar effect, even if people get the recommended 7-9 hours on average for adults aged 18-65 years," said study co-author Dr. Bastien Lechat. "These findings illustrate how irregularity in both duration and timing of sleep onset and waking up is a clear risk marker for poor cardiovascular health, along with the total number of hours we sleep."

Researcher Danny Eckert added: "This study highlights another concept in establishing good sleep habits which are vital for physical and mental health, in particular the cardiovascular system. It adds to what we already know about poor sleep hygiene and higher risk of obesity, cardiovascular disease and hyptertension in general."

Click here to read more in the journal Hypertension.