Ep. 48 – How much exercise is enough to reduce risk of disease?
This episode continues the thought from our last episodeon exercise. We’re looking at exercise that can reduce our risk of cardiovascular disease and cancer. How much is enough to be reduce that risk? Dr. Chet Zelasko explores this topic on this edition of Straight Talk on Health.
Welcome to Straight Talk on Health. I’m your host Dr. Chet Zelasko. Straight Talk on Health is a joint production with WGVU in Grand Rapids MI. I examine the world of health. Whether it’s research that makes the news, another miracle diet, or a new food fad, I look at the science behind them, and let you know whether it’s real or not. You can check out other things that I do on my website Drchet.com and sign up for my free emails.
On the last podcast, I covered a study that demonstrated that isometric exercise may be associated with lower systolic blood pressure (BP). Even though I covered the reasons for it from a physiological perspective, it still surprised me. The objective of this podcast is to examine the minimal amounts of exercise that have been associated with reducing the risk of cardiovascular mortality and the risk of cancer morbidity.
In case I haven't covered it recently, mortality is the death rate while morbidity is the sickness or disease rate. There are several cancers that are associated with sedentary living. The objective is to find just the right amount of exercise that can reduce the risk of developing those cancers. It goes without question that more can be better but in that 80% of the people don't exercise enough to do themselves any good come on we're trying to establish the minimal amount that may benefit reducing the risk of getting sick and dying. Let’s look at studies on exercise that can benefit your cardio vascular system in less time per day and can include the steps we may take in all physical activity.
The typical recommendation for aerobic exercise is 10,000 steps per day. Many scientists have examined that number for years to find the research on what it was based. Turns out that it was based more on marketing than on science. A Japanese company came up with the idea that we need to walk 10,000 steps a day. While completely made up, it has stood as the standard for years—until recently. Several studies have shown the actual amount may be between 4,000 and 7,000 steps per day. The next study help quantify it according to our minimalist approach
In a recently published study, researchers included data from 17 studies and over 225,000 subjects. They tracked the subjects for just over seven years to find out all-cause mortality and cardiovascular disease mortality. One more thing: the physical activity data were collected electronically as opposed to relying on some sort of mechanical device that underestimates or overestimates steps per day. They collected data from a variety of studies that all used electronic data tracking.
After using meta-analysis, the researchers used 3,900 steps per day as a baseline for the median risk of mortality. For every 500 additional steps per day, the mortality risk decreased 7% and for every thousand additional steps per day it decreased 15%. As the number of steps increased, the cardiovascular and all-cause mortality risk decreased until about 12,000 steps where it leveled off.
Going with our theme of doing just enough to reduce our mortality rate, it would seem that 4,000 steps per day, whether as part of your regular day or in addition to your everyday activity, gives a baseline of protection.
What about time? What if we just don’t even have the time to just do 4000 steps per day? We’re going to switch from mortality to morbidity. In this next study, the objective is to reduce the risk of getting one of thirteen types of cancer that are associated with sedentary living. Those cancers include colon, breast, endometrial, kidney, myeloma, liver, and non-Hodgkin lymphoma. This study was interesting for all kinds of reasons but mostly because they specifically looked at subjects who claimed they didn’t exercise regularly. The data were part of a sub-study of subjects that included the aforementioned wrist accelerometry data. The participants reported no leisure time exercise and one or fewer recreational walks per week. However, to be sure, they used a 7-day trial of wearing an accelerometer.
The purpose of the study was to test the relationship of unplanned vigorous activity to the diagnosis of cancers, especially those associated with the lack of physical activity such as breast and colon cancer. The researchers wanted to determine the dose of vigorous activity required to reduce the risk by 50% compared to maximal risk. They termed the activity Vigorous Intermittent Lifestyle Physical Activity or VILPA for short.
What would count as VILPA? Walking up several flights of stairs. Running to catch a bus or fast walking through an airport to catch a flight. Even rough-housing with kids might qualify.
There were 22,398 participants with a mean age of 62 years. Over the 6 plus years of follow-up, there were 2,356 new cancer events with 1084 diagnosed physical-activity related cancers.
They analyzed the data to find out how much VILPA per day was beneficial. One minute bouts and two minute bouts revealed the same dose-response curve. The more 1-2 minute bouts of VILPA that totaled at least 4.5 minutes per day, the lower the risk of developing cancer, especially a PA related cancer. In the discussion, the researchers talked about organizing VILPA in a training program. Of course they would. Organize the random.
We’ve looked at the amount of resistance training that helps reduce blood pressure, the minimal amount of steps needed to reduce mortality from CVD, and now, how to reduce the risk of some cancers by intense burst of exercise. There seems to be no doubt that some exercise, even in one minute intervals, can be beneficial.
Nowhere in these research papers did they suggest that this was the way to train athletes. You are not going to be able to power lift, run a marathon, or ride a 100-mile bike race. They all require something we’re trying to save: time. All these studies tried to find the minimum time to show how it could be beneficial. I think they succeeded.
You could wait until it’s put into an organized program or you could just do it right now. As long as your doctor says you can exercise, take the clothes off the exercise bike clothes rack in your bedroom, jump on, and peddle as fast as you can for a minute. Do that a few times a day. There’s your VILPA work for the day.
If your only goal is to prevent the risk of disease, this may be the way to begin, based on the most recent research. You might find you like the way you feel and begin to do a little more. Who knows? But first, you have to begin.
As you might expect, I’m not that random of a person. On those days when I focus on weight training, I do several 1-2 minute sprints on a stair climber or exercise bike within 10 minutes. On the days I’m doing walking or cycling for 30-45 minutes, I incorporate isometrics in my cool down and ab work. The benefit of this latest research is that whether you do the minimum or use the results to enhance your workouts, you are going to get some measurable benefit. And that’s better than no benefit at all. Get off it and get after it - even just a few minutes a day. We’re out of time for this show. Thanks for listening. This is Dr. Chet Zelasko saying health is a choice. Choose wisely today and every day.
JAMA Oncol. doi:10.1001/jamaoncol.2023.1830
Eur J Prev Card (2023) 00, 1–11 https://doi.org/10.1093/eurjpc/zwad2292
British J Sp Med Online July 2023. doi: 10.1136/bjsports-2022-106503