You can control blood sugar in Type 2 diabetes with exposure to sunlight, claims new study

Researchers say daylight exposure can strengthen the body’s circadian rhythm, which plays a key role in blood sugar control. (Image: Pexels)

Spending time in natural daylight—even while sitting indoors near a window—may help improve blood sugar regulation in people with type 2 diabetes, according to new research published in the journal Cell Metabolism.

Researchers from Maastricht University Medical School in the Netherlands, led by Professor Joris Hoeks, carried out a study. Their findings hint that natural sunlight exposure might boost metabolic health by reinforcing the body's internal clock.

How sunlight shapes our body's internal rhythm

The human metabolism follows a 24-hour body clock, which light exposure shapes. When this rhythm gets out of sync, it can lead to insulin resistance, poor blood sugar control, and metabolic issues.

To explore if natural daylight could help people with type 2 diabetes, the research team gathered 13 volunteers. The average age of these participants was 70 years.

The study put the volunteers in a room with a big window for 4.5 days. They got nine hours of natural sunlight each day, from 8 am to 5 pm. No artificial lighting was used during this period. Their daily routines—including sleep timing, physical activity, diet and diabetes medication—were kept constant.

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Under the same conditions, the participants later spent another 4.5 days in a windowless room exposed only to artificial lighting. This phase of the experiment was conducted about a month later.

What the researchers discovered

Scientists discovered that people's blood sugar levels stayed normal for half the time when they were in natural sunlight. In contrast, under man-made lights, their blood glucose stayed in a healthy range for about 43% of the time.

Professor Hoeks pointed out that extended periods of time outside the normal glucose range raise the risk of long-term complications, such as cardiovascular disease, even though the difference may seem slight.

Why sunlight could be beneficial

The effect, according to the researchers, is related to light-sensitive cells in the eyes that aid in controlling metabolic and circadian rhythms. Natural daylight contains a lot of short-wavelength (blue) light, which these cells react especially well to.

A better circadian clock promotes melatonin production at night and improves sensitivity. It also enhances fat metabolism, proper utilisation of energy and sleep quality. The study found that muscle cell clocks also function more steadily when exposed to daylight.

Experts warn caution

Professor Glen Jeffrey of University College London's Department of Visual Neuroscience commented on the results, calling them a powerful reminder of the significance of daylight for general health. He did, however, issue a warning that more extensive clinical trials are required to validate the advantages and ascertain how daylight exposure might be integrated into the treatment of diabetes.

Also Read: 10 ways to lower blood sugar naturally, approved by top cardiologist

What this implies for patients

Experts emphasise that while sun exposure may be a straightforward lifestyle support in addition to medication, diet, and exercise, it should not take the place of prescribed diabetes treatment.

FAQs on the effect of sunlight exposure on blood sugar

Sunlight exposure helps regulate the body's internal clock, which in turn can enhance insulin sensitivity and blood sugar control.

While spending time outdoors is beneficial, even sitting indoors near a window with natural light can help regulate blood sugar levels.

No, natural sunlight exposure should not replace prescribed diabetes medication but can be an additional lifestyle support.

In the study, participants were exposed to nine hours of natural sunlight each day. However, the exact amount of beneficial sunlight exposure can vary among individuals.

Extended exposure to sunlight without protection can increase the risk of skin cancer. It's important to balance sunlight exposure with proper skin protection.