A jousting knight wears his heart on his sleeve. Credit: iStock
In medieval times, a jousting knight would wear the colors of the lady he was courting tied around his arm. Hence, the phrase “Wear your heart on your sleeve” was born. Today, we use this romantic phrase to describe someone who expresses their emotions openly. How applicable that ancient phrase really is to maintaining a healthy heart!
In a landmark paper, a group of scientists discussed how stress and social interactions with others affected the health of the heart. It is well-known that stress is a major factor in the development of heart disease. This is because stress is a double whammy: It activates the “fight-or-flight” nervous response, and it causes inflammation in the cells that line blood vessels. Both of these events can damage blood vessels in the heart.
Research shows that positive social interaction expressing emotion is important for heart health. Support from a spouse or partner, friends or other groups can reduce stress and help you stick to a healthy diet and exercise program to minimize your risks.
Heart disease is the leading cause of death worldwide, with annual deaths creeping up to 24 million. Reducing stress and anxiety is an important aspect of keeping your heart healthy. Exercise, yoga, meditation and even deep breathing can promote a sense of calm when tensions mount. Try running or yoga with a friend or join an exercise class to keep you on track for a healthy heart. Go ahead, wear your heart on your sleeve—it’s good for you!
February is American Heart Month. You can find more information about keeping your ticker ticking on the American Heart Association’s website.
Many of us take our ability to read this blog or see the faces of our families and friends for granted. For the 10–15 million Americans with a disease called age-related macular degeneration (AMD), however, the loss of this ability is a daily and devastating reality. AMD is the most common cause of blindness in people over the age of 60.
There are many causes of visual impairment, including near-sightedness, far-sightedness, infection and diabetes. Some of these can be relatively easily corrected with eyeglasses and other medical tools and procedures. AMD currently has no cure, and we are just beginning to understand its causes.
AMD is a gradual and progressive deterioration of the retina, the light-sensing tissue at the back of the eye. The disease affects the most sensitive portion of the retina called the macula. We use the macula to distinguish fine features and colors, and when we lose this function, it can be devastating. AMD slowly causes the photoreceptors—cells that make up the retina—to die, creating blank spots in the field of vision. This occurs when undigested deposits of molecular debris called drusen accumulate in an area that eventually starves the cells that support the photoreceptors.
Genetics is the main factor that makes you more likely to get AMD. Other causes may include smoking and an unbalanced diet. Avoiding smoking and making healthy dietary choices are good ways to reduce your risk of AMD. A recent study published in the journal Cell Stem Cell found that a substance related to vitamin B3 reduced molecular debris and inflammation related to AMD in patients with the disorder. Fish, meat, peanuts and green vegetables all contain vitamin B3.
As the U.S. population grows older, diseases such as AMD are likely to become more prevalent and have a higher social and economic burden than they did in the past. Researchers are actively working to better understand the causes of the disease and how to treat and prevent it.
February is Age-Related Macular Degeneration and Low Vision Awareness Month. If you haven’t had your eyes checked yet this year, now is a good time to make that appointment.
Grant Kolar, MD, PhD, is an assistant research professor of pathology and ophthalmology at Saint Louis University School of Medicine.
The American Heart Association recommends that adults get at least 30 minutes of endurance exercise every day to keep your heart, lungs, and circulatory system healthy. A daily workout can help reduce your risk of developing diseases such as diabetes, heart disease and stroke. Endurance exercise is basically any activity that increases your breathing and heart rate for an extended period of time. Examples include:
- brisk walking
- climbing stairs
During exercise, your blood vessels expand (dilate), increasing blood flow, and delivering more oxygen to your working muscles. Over time, exercise helps your blood vessels become more flexible. This flexibility allows the vessels to dilate more quickly to deliver blood and oxygen to your muscles. Long-term endurance exercise also increases the number of small blood vessels (capillaries) in your body. All of these things help carry more oxygen to your organs and remove waste more quickly. As a result, you can enjoy better athletic performance, such as being able to jog farther, run faster or swim longer distances.
A recent study in the American Journal of Physiology—Heart and Circulatory Physiology showed that endurance activity may help blood vessels grow by increasing the number of microvesicles in your blood. Microvesicles are small particles that are shed into your blood from all types of cells in your body. When volunteers in the study rode a stationary bicycle, they produced more microvesicles than when they were sitting and resting. The number increased even more when they pedaled faster. The researchers then added the volunteers’ microvesicles to endothelial cells—a type of cell that lines the blood vessels and is responsible for expanding and contracting them. They found that microvesicles caused endothelial cells to grow twice as fast. In other words, when you exercise, the number of microvesicles increases, which in turn helps your blood vessels grow.
Now you know why exercise builds a better circulatory system, so get moving!
Dao H. Ho, PhD, is a biomedical research physiologist at Tripler Army Medical Center. The views expressed in this blog post are those of the author and do not reflect the official policy or position of the U.S. Department of the Army, U.S. Department of Defense or the U.S. government.
The thyroid gland—a small, butterfly-shaped gland found at the base of the neck—is the “Clark Kent” of endocrine organs. The thyroid’s actions are extremely powerful, but most people don’t know about its secret superpowers.
An endocrine organ releases substances called hormones into the bloodstream. These hormones are carried to other areas of the body where they have certain jobs to do. The thyroid gland makes hormones that affect many body parts, including bone, muscle, fat, skin, kidneys, and the brain (just to name a few). These hormones are also important for maintaining normal growth and proper metabolism—your body’s ability to convert food into energy.
If your thyroid gland is healthy, it usually means you’re at a healthy body weight and normal body mass index and have normal cholesterol.
People who have low thyroid hormone levels are often very tired, may be overweight and tend to feel cold. Those with higher-than-normal thyroid hormones can show signs of nervousness and heat intolerance and have significant and unintended weight loss.
The nutrient iodine is necessary for the thyroid gland to make thyroid hormones. This is why we have iodized salt: to provide enough iodine in our diet so that our thyroid works well.
January is Thyroid Awareness Month. Learn more about the signs and symptoms of an overactive or underactive thyroid from the American College of Endocrinology. Let’s keep our super thyroid gland super healthy!
Winter is here, and for much of the country, it’s going to stick around for a while. When exposure to frosty air and the constant hum of the heat pump continue for too long, you may end up with dry, itchy skin. We know that scratching an itch feels good, but why?
Researchers studied brain activity in two groups of volunteers. One group had chronic itching problems, and the other did not. The chronic itch group had more activity in the area of the brain involved with movement than the non-itchy group. This boost in activity means their brains were “wired” to scratch.
The non-itchy volunteers were then treated with an irritant that made their skin itch. The research team found that when the healthy volunteers scratched an itch, the reward center in the brain lit up. In other words, scratching feels good even if you don’t have a chronic skin condition.
Slathering yourself with moisturizer and drinking more water can help hydrate the skin—your largest organ—and keep winter itches at bay. But sometimes you just want relief from a good—yet gentle— scratch. Now you know that your brain is giving you permission to indulge.
– Erica Roth
With winter upon us, it is a good reminder that cold weather is not an excuse for inactivity. Athletes from cold-weather climates, such as the Nordic countries, are not content to stay indoors during winter. In fact, cross-country skiers from these colder climates might be considered the premier human aerobic athletes.
Although some picture cross-country skiing as slowly shuffling along at a leisurely pace, the reality of competition is much different. For example, the winner of the 50 km (31 miles) freestyle at the 2014 Winter Olympics finished the race in less than one hour and 47 minutes. That’s longer than a marathon but finished in less time. And these races typically go uphill for 50 percent of the time!
Physiologically, skiing is interesting from many perspectives. The biomechanics of skiing are interesting because the arm and leg movements must be coordinated to efficiently move forward. The whole-body nature of skiing makes the physiology fascinating to study. Cross-country skiing puts large demands on the heart to deliver blood and oxygen to exercising muscle. This challenge is greater than for running or cycling (which engages only the legs) because both the arms and the legs need to work with skiing.
The amount of blood going to the arms versus the legs constantly changes, too. These changes are based on the hundreds of technique transitions needed to cross the varying terrain during a race. The great physical endurance required improves the ability of cross-country skiers’ muscles to use oxygen. These athletes have some of the highest levels of oxygen consumption (VO2max) on record. Legendary physiologist Bengt Saltin and other researchers have used the unique whole-body nature of cross-country skiing to study blood flow delivery. This approach has provided us great insight into the regulation of blood flow in both athletes and non-athletes.
Cross-country skiers demonstrate that cold weather is not an excuse to be sedentary, but rather an excuse to be great.
Benjamin Miller, PhD, is an associate professor in the department of Health and Exercise Science at Colorado State University. He co-directs the Translational Research in Aging and Chronic Disease (TRACD) Laboratory with Karyn Hamilton, PhD.
The start of a new year can feel like a fresh slate or an unwritten book. It’s a chance for many of us to resolve to do things better (eating, exercising) or to stop doing certain things altogether (smoking). But most people don’t succeed in sticking to their resolutions in the long term, and the reason might surprise you. It’s not always a question of lacking willpower or being lazy. Keeping resolutions makes your brain work hard, and that mental effort takes time and practice.
Researchers from the University of Minnesota found that your brain uses more than one decision-making system to build and regulate habit-forming and goal-directed behaviors. One system looks at the steps you take to make a decision. Another evaluates your actions and decides when you need to change a new behavior in order to receive a reward.
Here’s where the hard work comes in: The researchers explain that goal-directed behavior requires mental energy and planning. You have to plan ahead before making decisions to know how to reach your goal. Let’s say, for example, you’re trying to cut back on sweets and are invited to a party. If you want to enjoy a dessert at the party but don’t want to completely ignore your resolution, you’ll need to plan to eat less sugar during the rest of the day. Over time, as you keep making more goal-oriented decisions, the choices become more automatic.
Another study suggests that nerve cells stick together when you form a habit that you’ve enjoyed (such as eating dessert after dinner). The strong bond they create can be tough to break, and—like getting up early to go running or sticking to that diet—it isn’t always easy. This is especially the case when your emotions take over and you feel resentful or angry at the challenging changes you’re trying to make. Being mindful and keeping your emotions out of the decision-making process can help. Your brain, like your body, just needs time to adjust to your new routines.
Good luck and happy new year.
– Erica Roth
It’s been a physiology-full 2016 on the I Spy Physiology blog! From exercise to respiration to heart health and beyond, we’ve explored how the bodies of humans and other animals work, adapt and react. Today, we take a look back at our 10 most read posts of the year.
Concussions among football players was headline news in 2016. Against this backdrop, our most popular post of the year looked at how woodpeckers can bang their heads roughly 12,000 times a day at a greater force than the average football hit without sustaining a head injury. Posts about the amazing endurance of Iditarod sled dogs and a researcher’s excellent explanation of what physiology is and why it’s important round out the top three. Check out this year’s top 10:
If you’ve got a topic that you’d like us to cover in 2017, we’d love to hear from you! Share your thoughts in the comments or send us an email.
Winter officially begins next week with the winter solstice—the day of the year with the fewest hours of sunlight—on Dec. 21. With the cold weather and shorter days, you might be tempted to curl up under a blanket until the spring thaw. Whether you plan to hibernate or get outside to enjoy the chill, we’ve got some good reads about how our physiology responds to the cold weather.
Check out these throwback posts featuring cold weather tips to help you stay safe and healthy during the coldest months:
Have fun, be safe and take note of how your body adapts to the season!
– Stacy Brooks and Erica Roth
It’s 7:30 a.m., I’m looking for my keys, grabbing my bag and herding everyone out of the door as we hurry off to school and work. Wait! One more trip back into the house for the forgotten homework assignment, a lunchbox and … it seems I have forgotten several things. Is it stress, lack of sleep or just the natural aging process? Regardless, it seems I need a memory-boosting workout.
Exercise is no longer just for affecting the size of your muscles, but also the size of your brain. As we age, the volume of our brain naturally decreases. However, in people at risk for Alzheimer’s disease, one of the numerous cognitive diseases under the dementia umbrella, there is a more marked decrease in brain volume. Being physically active has been shown to slow or even stop the decrease in brain volume in older people, even among those at risk for Alzheimer’s disease.
The Physical Activity Guidelines for Americans issued by the U.S. Department for Health and Human Services state that adults should get 150 minutes of moderate-intensity activity—such as walking, running, swimming and cycling—each week to promote and maintain health. These and other forms of moderate-intensity exercise have also been positively linked to maintenance of memory and learning as we age.
According to a recent study in the research journal Alzheimer’s and Dementia, reaching recommended physical activity goals has substantial effects on brain volume. Ninety-one adults ranging from ages 50 to 74 wore an accelerometer, a device which records and measures the wearer’s steps and speed of movement, for seven days. Subjects who performed physical activity for 150 minutes or more per week had temporal lobe sections that were 5–6 percent larger than their sedentary counterparts. The temporal lobe of the brain is associated with learning and memory. This sustained brain volume associated with physical activity was noted among people with a family history of Alzheimer’s disease, those who have the Alzheimer’s associated gene and those who were not at high risk.
The moral of the story? Get up and move. Your brain will remember to thank you.
Jessica C. Taylor, PhD, is an assistant professor of physiology in the College of Osteopathic Medicine at William Carey University in Hattiesburg, Miss.