Dear Doctors: I’m 65 and healthy. I actually like shoveling snow because it keeps me active. My grandson and my wife say I’m asking for a heart attack and are after me to get a snowblower. I would like to know how serious a risk shoveling really is. Surely there's a way to shovel snow and stay safe.

Dear Reader: Shoveling snow is a vigorous activity. It uses large muscle groups and involves trunk rotation. Because it involves so much of the body engaged in lifting weight, it also becomes aerobic. Just as quickly, it can outpace the heart’s capacity. This is particularly true for people who are more sedentary. Both of us -- Dr. Glazier as a medical student in New York and Dr. Ko as a resident in Rhode Island -- have seen our fair share of snow-induced cardiac issues. Your question opens up a discussion we suspect can benefit many readers who ride out the winters in snow country.

Physical exertion is measured in metabolic equivalents. Also known as METs, it's a sliding scale that indicates how much energy you’re using during a particular activity. The scale starts at one MET, which is sitting quietly. From there, it increases exponentially, with 18 or 20 METs representing a sustained flat-out, hair-on-fire sprint. Shoveling snow clocks in around 5 to 7 METs. This is about the same as a vigorous game of doubles tennis. It also marks an important transition zone, where you progress from moderate to vigorous exertion. Cardiovascular demand spikes at this point, often without people realizing it.

By the time danger signs appear, the heart may already be under significant strain. These signs include shortness of breath; weakness; dizziness; chest pressure or pain; a racing, pounding or irregular heartbeat; nausea; or sudden fatigue. Another factor to consider, unique to winter weather exertion, is something known as cold-induced peripheral vasoconstriction. In cold weather, the blood vessels closest to the surface of the skin tighten up. This sends warming blood deeper into the body to protect vital organs. However, this can cause a spike in blood pressure that, for some people, can be dangerous.

Exercise physiologists have found that in just two minutes of shoveling snow, your heart rate can exceed 85% of maximum. That's on par with a stress test. To stay safe, work at a slow to moderate pace and be sure to take frequent breaks. Sweep or push away what you can and keep the heavy lifting to a minimum. When you lift, don't fill the shovel all the way. And don't forget to breathe. Because the core is engaged, it can be easy to unconsciously hold your breath as you work, which causes blood pressure and heart rate to rise. If you experience any of the symptoms we noted above, stop immediately. And one final note: Anyone living with heart disease or who has the risk factors for heart disease should not shovel snow.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctors: Is it OK to go without shoes? I’ve heard conflicting information. I wear supportive shoes for exercise and in public, but I prefer bare feet at home. I stand about six hours a day, and I just find it much more comfortable without shoes. I am 65 and healthy, with no history of foot problems.

Dear Reader: It’s not surprising that you have run into different advice about going barefoot. While opinions on the subject tend to be based on health concerns and issues of hygiene, they can also sometimes be due to cultural views and norms. That said, there is no universal guidance on the practice. The answer is based on each person’s health and well-being. Nonmedical factors such as climate, the surfaces on which the person is standing or walking, and their daily activity levels also play a key role.

For most healthy people, going barefoot indoors does not pose a health risk. In fact, proponents say that spending time without shoes on can add strength and flexibility in the feet and ankles, improve circulation and help with posture. When people are free from footwear, they often become more aware of the countless muscular microadjustments we make to stay balanced as we move and stand. And as you point out in your letter, for many people, going barefoot just feels good.

That said, there are a few important points to keep in mind. There are situations where extended time barefoot is not advisable, like with structural problems in the feet or ankles. Examples include flat feet, fallen arches, bunions, plantar fasciitis, arthritis, fat pad loss or a tight Achilles tendon. People living with diabetes must also be careful about going barefoot. The disease can impair circulation, particularly in the feet. Even a slight scratch or cut can quickly escalate into a more serious health concern.

Going barefoot can also be a health risk for people living with neuropathy. This can also apply to people with poor circulation not related to diabetes. It’s inadvisable for people with a history of foot ulcers or balance problems that raise the risk of a falling. Those living with health conditions or undergoing medical treatments that weaken the immune system may need to take caution.

When going barefoot, you need to think about safety. Wood, tile, stone and laminate floors can each have rough, jagged or uneven surfaces that can cause a wound. Carpet is forgiving, but it can camouflage hidden dangers such as a tack, nail or shard of broken glass. Cleanliness is also an issue. Bacteria, dirt, dust and other germs continually migrate indoors with human and pet traffic. Some fungi, including the one that causes athlete's foot, are contagious and can be transmitted on shared flooring. Choosing to go barefoot also adds a daily task: washing your feet to keep things hygienic.

You have shared that you are in good health, don’t have problems with your feet and keep going barefoot a strictly indoor activity. In this scenario, you meet the criteria for safely ditching your footwear for a few hours a day.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctors: You recently stated in a column about eye floaters that there is no cure at this time. I got a vitrectomy for this condition, and it was life-changing for me. By no means is this procedure meant for everyone as it is not without risk, but there is a cure!

Dear Reader: Eye floaters are so common, an explanation of the term may not be necessary. About 70% of adults have them to some degree. For those lucky enough to not know what we’re talking about, we’ll explain: Floaters are tiny clumps of collagen, protein and other cellular debris that drift through the vitreous. The vitreous is the gel-like substance that fills the back of the eye. Because these particles block the path of light entering the front of the eye, they cast shadows on the retina that can appear as specks, strands or cobweblike shapes.

In most cases, floaters aren’t a risk to eye health. For some people, they can be severe enough to interfere with vision. Extensive floaters can make it hard or even impossible to engage in daily activities such as reading, working at the computer or driving. They can also interfere with visual clarity in low light and adversely affect night vision. When floaters become severe and persistent, doctors may recommend the surgery you had.

A vitrectomy is surgery to remove the vitreous from the eye. The doctor makes small cuts, then suctions out the vitreous. Because the vitreous helps maintain the shape and volume of the eyeball and holds the retina in place, they then replace it. In most cases, they replace it with a sterile saline solution. If there are other retinal issues, they may use a bubble of air or gas or silicone oil.

This is usually an outpatient surgery, and you return home the same day. Side effects can include redness, swelling and a few days of blurred vision. Patients use a temporary eye patch and eyedrops to reduce swelling and prevent infection during recovery. Patients must restrict their driving during the initial recovery period. It is also important to avoid physical exertion for a few weeks. If the eye is refilled with a gas bubble, patients may need to keep their head in a downward position to keep the bubble pressed against the retina. Patients must also avoid high altitudes or flying until cleared by their doctor.

As you note in your letter, this surgery isn’t for everyone. Risks include bleeding, infection, retinal detachment, glaucoma, cataract formation and possible changes to vision. As a result, vitrectomy is often reserved for severe cases where floaters are severely impacting quality of life. Someone with severe floaters should begin by seeing an ophthalmologist who specializes in this condition. They will assess your situation and help you to understand the risks and benefits, other treatment options and what to expect if you proceed. We are happy to know that your own surgery went well and that it resolved the visual problems you had.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

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