Author: C. Michael Wright, MD
Welcome to my blog on circadian rhythms and their effects on cardiovascular and metabolic health! Hopefully I will be able to shed light (no pun intended!) on how all our body clocks work together to control many of the risk factors that lead to metabolic syndrome, diabetes and cardiovascular disease.
I have spent most of my career as a preventive cardiologist and clinical lipidologist. Yet only recently, when I discovered Dr. Panda’s lab, which is just down the street from my office at Scripps Memorial Hospital in La Jolla, did I learn of how important circadian rhythms are to the kind of work that I do.
Every day I see patients with a spectrum of metabolic abnormalities that provide the perfect milieu for the development of diabetes and cardiovascular disease. As a physician, I have a deep knowledge of the medications available to treat specific diseases. For example, there are many classes of medications to treat hypertension. The same is true for high cholesterol, high triglycerides, diabetes, coronary artery disease, congestive heart failure and cardiac arrhythmias. But are these really all separate and unrelated conditions?
In 1988, Gerald Reaven published a paper entitled “Role of insulin resistance in human disease” in the journal Diabetes. He observed that high blood pressure, high blood sugar, high triglycerides, low HDL cholesterol and obesity are often found together in people with a condition called insulin resistance, and that this condition is very common in people with cardiovascular disease. Dr. Reaven had been trying, since the early 1960’s, to convince the medical community of the importance of insulin resistance in both type 2 diabetes and heart disease. In 1988 he coined the term Syndrome X, but today we call it metabolic syndrome.
Insulin resistance is the underlying condition that often leads to all the diseases I mentioned in the previous paragraph. As you can imagine, when we treat each of these conditions separately it can lead to a patient taking so many medications that the potential for side effects and adverse reactions is exponential. Going one step further, we might say that insulin resistance is caused by disruptions in energy homeostasis (equilibrium). Energy homeostasis is the central problem that all living creatures grapple with for survival. Now we are learning that biological clocks have been around since single celled organisms appeared, precisely to help with, among other challenges of life, maintaining energy equilibrium.
What we need more of in medicine are unifying observations that explain how separate conditions can stem from a common underlying pathophysiology. This is where circadian rhythms enter the picture. As I delved into Dr. Panda’s work on time restricted feeding in mice it was like discovering the secrets hidden deep within the cells of our body that provide the ultimate unifying theory of disease. We are whole and healthy when all the clocks in our organs and tissues are ticking at the correct time, i.e. coordinated. When this harmonization is disrupted it exposes our bodies to metabolic abnormalities that, over decades, produce the chronic diseases of aging, including cancer, cardiovascular disease, diabetes, Alzheimer’s and many others. The science of circadian rhythms and their effects on aging and disease is still in its infancy. Please join us on a voyage of discovery that may ultimately lead to interventions, including lifestyle modifications, neutraceuticals and medications that may well have the potential, through their interactions with circadian clocks throughout the body, to protect us from the ravages of chronic disease, and allow us to age gracefully, so that we can enjoy to their fullest the fruits of a lifetime of labors!