Redefining the Physically Fit Heart

When evaluating fitness levels, a basic question is whether my (ambulatory) patients can walk up 2 flights of stairs (~20-30 steps) without stopping.  The answer is most revealing when they disclose the need to stop to catch their breath and/or experience heart-related symptoms that are new or progressive.

A new study helps to redefine the physically fit heart.  Conducted in Spain, study volunteers climbed 4 flights of stairs (60 steps) at a fast but comfortable pace.  Those able to complete this task within 45 seconds were found to have a heart workload ~10 METS; this workload was associated with a normal stress test (and presumably, normal heart function), in the vast majority of study subjects.  By contrast, stair climbing that took at least 90 seconds (correlating with a heart workload of less than 8 METS) was associated with an abnormal stress test (and presumably, heart disease) in ~60% of study volunteers.

The Metabolic Equivalent of Tasks (METS) is the amount of energy used during physical activity.  One MET equals activity at rest with higher levels representing increased intensity of a given activity.  From a cardiovascular standpoint, a physically fit heart is one that is able to generate a workload of at least 10 METS, as demonstrated by the stair climbing activity above ; this translates to a low annual cardiovascular death rate (1% and lower).  Inability to achieve 8 METS, however, translates into a considerably higher annual cardiovascular death rate (2% and greater), a rate typically observed in men and women with established heart disease.

(For the record, I clocked in at 37 seconds (with surgical mask-on) for my 60-step jaunt earlier this week en route to my outpatient cardiology center).

Listed below are several tips I make to my patients regarding exercise for the heart.  More detailed recommendations can be found in my chapter Lighthearted and Light on Your Feet from “Heal Your Heart”.

1. Aim to walk approximately 5 miles a day:  Keep track of your daily activities using a pedometer or similar tracking device (iphones have a built-in “health app” that automatically tracks your daily activities).  Every 2,000 steps equal ~1 mile; 10,000 steps is equivalent to 5 miles.
2. Aim for a walking rate of 3-5 miles per hour (mph):  When it comes to heart health, the sweet spot is walking at a “brisk” rate of 3 to 5 mph.  If you are walking on a treadmill, start off with a 5-10 minute warmup period (2-3 mph), then engage in the higher walking rate for 20-30 minutes followed by a 5-10 minute cool down period.
3. Arise and stretch every 20-30 minutes at work: In the age of COVID, many of us have spent more time working from home. If you have a sedentary job, make sure to stand and stretch at least twice each hour.  When watching TV, I advise my patients to stand up and stretch during commercials.   Stand and stretch twice each hour when watching Netflix, Amazon or other movies at home.
4. Build in light weight toning and stretching exercises:  A healthy physical activity regimen should incorporate light weights and stretching to stabilize and improve balance & coordination in order to reduce fall risk.  Engaging in aerobic activities and weight toning exercises, reduces cardiovascular risk by 20-30%.
5. Try Walking Backwards at Home: Walking backwards has been shown to improve balance, coordination and various brain functions such as attention span and memory. Find the longest room in their home and start walking forward and backward for 5 minutes on day 1 with progression to 10-15 minutes daily.

Michael Miller, MD is Professor of Cardiovascular Medicine at the University of Maryland School of Medicine.  Check out his HeartHealth Tip of the Day on Twitter @mmillermd1 and book “Heal Your Heart…” at your library, bookstore or online.