If a person’s circadian rhythm is broken, even a low-salt diet may increase resting blood pressure and the risk of vascular disease. There are many factors that can alter or change a person’s circadian rhythm, including disrupted sleep, shift work, aging, and disease. A circadian dysfunction can contribute to high blood pressure, and although a low sodium diet is advised to help lower blood pressure, a circadian dysfunction can still lead to high blood pressure – even with proper diet in place.

Dr. Daniel Rudic, vascular biologist in the Department of Pharmacology and Toxicology at the Medical College of Georgia at Augusta University, said, “Circadian rhythm is the daily rhythm in our bodies, and probably the most well-known is that of waking and sleeping.” Although complex molecules are involved in regulating the circadian rhythm, it is the daytime-nighttime cycle that resets our biological clock.

When we are resting or sleeping, our bodies are able to take a break. Rudic added, “Blood flow to your organs is going to change when you are sleeping. Your heart rate is going to decrease. One well-known observation is that the blood pressure exhibits a circadian rhythm.”

“Our data suggests that low salt does what it should do in a normal mouse: it lowers blood pressure. But when we fed a low-salt diet to a mouse that had a circadian dysfunction, basically a sleep disorder, low sodium actually causes this nondipping blood pressure and vascular disease,” Rudi said,

A low-salt diet can help reduce blood pressure as sodium is an integral part in blood pressure regulation. Blood pressure medications target the renin-angiotensin-aldosterone system, which is stimulated by salt. Although Rudic does not suggest abandoning a low-salt diet for treating high blood pressure, the study stresses the difficulty of managing blood pressure.
For the study, the researchers used the mice with one of the genes responsible for the circadian rhythm knocked out and found they had the same blood pressure as normal mice with the gene. The mice without the gene were given a vasoconstrictor. Their blood pressure did not lower at rest, and vascular disease accelerated.

It is expected that blood pressure lowers on a low-salt diet, but this did not occur in the knocked-out gene mice and it did not dip in the daytime for nocturnal mice either. Chronic consumption of a low-salt diet was also found to narrow and impact blood vessels. When the mice were given a drug to target the renin-angiotensin-aldosterone system, the nondipping problems were resolved.

Rudic explained, “Even though we can’t currently directly target the circadian clock, clearly you can fix aspects of what the clock is influencing with antihypertensive medication.” He suggests that additional research is required to determine when the right time is for patients with a circadian dysfunction to take blood pressure medications.

Circadian rhythm helps to determine vulnerability to disease

Certain diseases and health conditions have been found to occur more frequently at certain times of the day. For example, heart attacks are most common in the morning and epileptic seizures have been found to peak in the afternoon. Researchers are finding that our circadian rhythm may play a role in this phenomenon as it cycles every 24 hours, affecting all systems in our bodies.

Chronobiology is the science that studies the body’s internal clock mechanisms. Certain genes help keep our biological functions in sync with changes in light and darkness. This explains the hormonal changes throughout the day.

An ever-changing circadian rhythm can increase a person’s vulnerability to disease. If there is a circadian dysfunction, hormones can become unregulated, producing too much or too little. As a result, our organs can’t get the proper rest they need to restore themselves. These factors can increase the susceptibility to illness.

There are many crucial events that should normally occur at night time when we rest, as added activity during the day increases the stress on the body. The immune system may become overactive, worsening the symptoms of conditions like asthma or arthritis. This is why researchers are working to better understand the circadian rhythm in order to develop more effective treatment options by targeting our biological clock.

Natural balancing tips for circadian rhythm

Until doctors and researchers uncover strategies to specifically target the circadian rhythm, there are natural ways you can go about improving your own rhythm. These tips can help you rebalance your circadian rhythm in order to reduce the risk of illness.

• Keep your daily schedule as routine as possible.
• Maintain a consistent sleep/awake schedule – sleep roughly at the same time, enjoy your meals roughly at the same time.
• Practice good sleep hygiene – if you wake up tired in the morning, go to sleep earlier and avoid caffeine in the afternoon.
• Limit alcohol consumption – especially prior to bed.
• Avoid overnight flights and other jet lag scenarios where possible – make adjustments if you must encounter jet lag.
• Avoid shift work if possible, and if you must perform shift work, maintain a regular routine.

By following these tips, you can have better success in maintaining a normalized circadian rhythm.

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