In Japan, the term Karoshi means “death from overwork,” and is based on the phenomenon of sudden death in previously healthy people who suffered either a stroke or heart attack when exposed to severe workplace stress. Scary? Well, it is. The good news is: It is possible to understand the adverse signalling between the brain and heart during stressful times, and to help the heart avoid developing a disease and survive.
Brain and heart have a dynamic relationship
Our brains create a protein called brain-derived neurotrophic factor (BDNF), which helps the brain and nervous system to grow, helps the nerves to communicate, and is involved in the ability of nerves to change and adapt. Simply put, it functions in those parts of the nervous system that are needed for repair, learning, and memory. In addition, when levels of this protein are high, BDNF is thought to be a natural antidepressant.
A team of researchers from Johns Hopkins University recently learned more about how BDNF signals the heart and affects its function. BDNF binds to the heart through a receptor called TrkB (tropomyosin-related kinase receptor. As BDNF increases and binds to TrkB, it helps the heart’s blood vessels and nerves to grow and develop.
Another way the brain works on the heart when it encounters stress is by stimulating nerves to release adrenalin, which makes the heart beat quicker and with more force. When BDNF is low, or the heart is not receptive to it, the heart remains sensitive to adrenalin. The combination is problematic, because a heart that is not sensitive to BDNF and is unable to adapt to stress becomes exposed to stress and can rapidly weaken and fail.
BDNF linked to many heart problems
- Perhaps low levels of BDNF can explain how depression causes heart diseases and increases the risk of dying after a heart attack, heart failure, or atrial fibrillation, regardless of your treatment.
- Certain chemotherapies for cancer can cause the heart to fail. It may be because some chemotherapies block the heart receptor to the BDNF protein, blocking BDNF signal pathways from the brain and heart.
- The Hopkins study may provide clues about why some endurance athletes develop premature heart failure and heart arrest. Perhaps athletes who have repeated exposure to adrenalin have acquired or genetic interruption in the brain-heart BDNF signalling pathway that predisposes their hearts to fail.
- Release of BDNF and response to it may explain why some people with heart failure recover, while others experience progressive deteriorating disease.
- Clearly, this pathway may be used to create drugs that can replicate BDNF, improve the heart’s response to it, or increase its natural production. In the meantime, there are possible ways to raise your natural BDNF.
Raising levels of BDNF, the heart-protective protein
- Eat a diet rich in whole foods, such as fruits and vegetables. Studies show that a diet that is high in fat or refined sugar lowers brain BDNF.
- Researchers recommend reducing your meal size and occasional fasting to raise BDNF. This may explain emerging research that has shown positive health benefits such as lower blood pressure, cholesterol, and diabetes risk with occasional or regular fasting.
- Increasing your consumption of omega-3 polyunsaturated fatty acids can increase BDNF in as little as six weeks. Foods rich in these include green leafy vegetables, nuts, fish, and seeds.
- Studies suggest that exercise increases brain BDNF. Along with ensuring good overall health, it also is a power antidepressant, perhaps in part through raising BDNF.
- Your quality of sleep can also impact BDNF. Research shows that when you get restorative, quality sleep you can increase your BDNF. For most of us, this appears to be between 7 and 8 hours a night.
- One very important way to raise the amount of natural BDNF is through relationships. Our health needs quality relationships with spouses, children, and friends. Our children need quality relationships with their parents. Studies show that positive and sustaining relationships can raise BDNF.
The research has provided some interesting clues to the mind-body relationship. It provides another glimpse into the complex and real interactions between body and mind. As science catches up to clinical observations, we learn of the complex signalling processes that govern them. By understanding these processes, we can understand the role of lifestyle changes and interventions and develop new therapies to prevent disease.