Monthly Archives: February 2014

Sleep Impacts Cancer

We have become a 24-hour society where people can work, shop and exercise at all hours of the day or night. But just because we can, does that mean we should?

Humans evolved in a rhythmic world, with daily and seasonal variations in light, temperature, and food availability. In our modern world we can control all these environmental factors so they are the same throughout the year, but our body is still programmed for circadian variation. Cancer incidence increases when people live out of sync with natural rhythms, like those who do shift work.

Shift Workers at Increased Cancer Risk

Those people who work graveyard shift have an increased risk of breast cancer. This risk increases with the number of years graveyard shift has been done. Getting bright light at night suppresses our natural melatonin surge. Melatonin is a powerful anti-oxidant, protecting our cells from damage.

Shift workers also are at increased risk for:
•Hypertension
•Cardiovascular disease
•Duodenal ulcer
•Elevated stress hormones
•Menstrual irregularities

Cancer Causes Sleep Disruption

The sleep – cancer relationship goes both ways. For those people undergoing cancer treatment, sleep disruption can be a symptom. This can be a side-effect of chemotherapy, or of pain, or other factors.

The good news is that several studies have shown that sleep of cancer patients can be improved by doing Cognitive-Behavioral Therapy for Insomnia. Specifically, after treatment, cancer patients ended up sleeping a higher percentage of the time they were in bed, had improved mood, and decreased fatigue. Another study additionally found that the people had fewer nights on medication, and that the improvements were maintained for 12 months afterwards.