Prime Time Replay:
Paul Williams, Ph.D.
on the results of the
National Runners' Health Study in 1991
MsgId: *breakthrough(1)
Date: Wed Oct 15 21:53:56 EDT 1997
From: moderator At: 152.163.205.217
Hi, I'm Madeleine Lebwohl, and tonight I'll be speaking with Paul Williams, Ph.D., of the Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California. Dr. Williams will be with us tonight in an in-studio interview. Welcome, Dr. Williams!
MsgId: *breakthrough(3)
Date: Wed Oct 15 21:56:16 EDT 1997
From: moderator At: 152.163.205.217
PTW: Hello, its a pleasure to be here.
MsgId: *breakthrough(4)
Date: Wed Oct 15 21:57:24 EDT 1997
From: moderator At: 152.163.205.217
Dr. Williams conducted the National Runners' Health Study in 1991, and tonight we'll be discussing results of that work.
MsgId: *breakthrough(5)
Date: Wed Oct 15 21:59:07 EDT 1997
From: moderator At: 152.163.205.217
PTW: Currently we have 55,000 runners involved in that study, and the study is unique in several aspects. It is the only study to look exclusively at vigorous exercise. This is the sort of exercise that makes you breathe hard and sweat. And its also unique in that it was designed to specifically look at exercise, whereas other studies have merely tacked on exercise to other existing studies.The government currently recommends moderate exercise. And these can be exercises such as walking briskly, but also cleaning your house and mowing your lawn and other gardening. One of the really important contributions of this study has been to challenge the notion set forth by the government emphasizing that moderate exercise, provides most of the health benefits. The government has exphasized moderate activity, we think, because it was a pragmatic decision. They thought that this sort of recommendation would be the most condusive to getting totally sedentary people to exercise. However we think that the sword has two edges.
While encouraging totally sedentary people to become more active, the recommendations may also discourage people who have incorporated vigorous exercise into their life. They may be asking themselves, why should I be exerting myself beyond the point that is being recommended. Our research shows that the health benefits of vigorous exercise continue to accrue throughout a very high level. In fact, men who are running over 40 miles per week, are estimated to have 30% less risk of heart disease than those running less than 10 miles per week. We also find that in women, the more miles they run, the lower the estimated risk of heart disease. And while we don't that everybody is going to start to run 40 miles per week, we do believe that people will benefit throughout the entire range of running mileage, up to this point. With the more miles run, the lower the risk factors for heart disease.
MsgId: *breakthrough(13)
Date: Wed Oct 15 22:10:37 EDT 1997
From: moderator At: 152.163.205.217
People have only been running in leisure time in recent history. Can this exertion be correlated to other vigorous activities -- what if you can't run?
MsgId: *breakthrough(14)
Date: Wed Oct 15 22:12:05 EDT 1997
From: moderator At: 152.163.205.217
PTW: We think that the key characteristics of the type of activity we're studying is that its sustained and vigorous. For this reason, we believe that the benefits also apply to swimming, cycling, and aerobic workouts, provided they are sustained and vigorous.
MsgId: *breakthrough(15)
Date: Wed Oct 15 22:12:47 EDT 1997
From: moderator At: 152.163.205.217
What is vigorous -- sweating? Out of breath? Anything else?
MsgId: *breakthrough(16)
Date: Wed Oct 15 22:14:08 EDT 1997
From: moderator At: 152.163.205.217
PTW: Vigorous exercise is defined scientifically as exertions that consume six times more energy than your resting metabolic rate. And I think a good, practical definition is that its those activities that make you feel like you're really exerting yourself.
MsgId: *breakthrough(17)
Date: Wed Oct 15 22:15:51 EDT 1997
From: moderator At: 152.163.205.217
How can you maximize this benefit? What do you have to do relating to your nutrition, or other habits, to keep the benefit. Does what you do in between exercising cancel the benefit out?
MsgId: *breakthrough(18)
Date: Wed Oct 15 22:17:25 EDT 1997
From: moderator At: 152.163.205.217
PTW: Exercise adds to the rest of your life. We are finding that different health behaviors often have an additive effect. So if you're following a good diet, and exercising, both are likely to be beneficial. On the other hand, if you're working as hard as possible to make yourself unhealthy, there's only so much exercise can do.
MsgId: *breakthrough(20)
Date: Wed Oct 15 22:18:30 EDT 1997
From: moderator At: 152.163.205.217
You're also doing a walking study. How does that stack up next to the running study?
MsgId: *breakthrough(21)
Date: Wed Oct 15 22:19:59 EDT 1997
From: moderator At: 152.163.205.217
PTW: Let me begin by saying that we think that exercise is an investment, and the more exercise you do, and the more vigorous the exercise, the greater the benefit. This means we expect there to be benefits among less intensive exercise as well. But we need better data on exactly what those benefits are.For that reason we have started the National Walkers' Health Study. This study is being carried out in cooperation with Walking magazine, in completely parallel fashion to our study of runners. We currently have 5,000 walkers, and are attempting to recruit an additional 50,000 before the end of next year.
MsgId: *breakthrough(24)
Date: Wed Oct 15 22:23:31 EDT 1997
From: moderator At: 152.163.205.217
That's a great response. How do you get so many people to take the time to be part of your studies?
MsgId: *breakthrough(25)
Date: Wed Oct 15 22:25:01 EDT 1997
From: moderator At: 152.163.205.217
PTW: We believe we get a very enthusiastic response to our surveys because we're asking questions about things that really interest these people. People who are involved in physical activities tend to be really interested in this research. They are making an effort and they want to make some intelligent decisions about how they should pursue walking.For example, are three short walks as good as a long walk. Is it important to incorporate a very long walk each week. And how fast should they walk? We believe that by having a very large cohort we can answer questions such as these as they relate to the risks of heart disease and cancer.
People interested in our study can ask for a questionnaire by email: (PTWilliams@LBL.gov) We hope to have our walking questionnaire on line before the end of November. Until then we will send out paper questionnaires for people who are interested. People should make sure to include their address in the request for a questionnaire.
MsgId: *breakthrough(28)
Date: Wed Oct 15 22:31:10 EDT 1997
From: moderator At: 152.163.205.217
When you say that exercise has dividends in other parts of your life, what have you found in runners in your study?
MsgId: *breakthrough(29)
Date: Wed Oct 15 22:32:41 EDT 1997
From: moderator At: 152.163.205.217
PTW: Some of the more intriguing results have to do with maintaining body weight. Earlier this year we looked at men of different ages and observed that regardless of how much they ran they seemed to gain weight with age. This is looking at men as they went from under age 30 to age 50. The only way to avoid this age related weight gain -- or middle age spread -- was to increase your exercise as you got older. In fact, we estimate that men should be adding about 1.4 miles in their weekly running routine annually to keep from expanding their waistlines as they get older. The sad truth is that most men become less active as they go through middle age.
MsgId: *breakthrough(31)
Date: Wed Oct 15 22:36:12 EDT 1997
From: moderator At: 152.163.205.217
Is there any thought about why the middle age spread happens? If its so bad for health, why has evolution put it there?
MsgId: *breakthrough(32)
Date: Wed Oct 15 22:38:23 EDT 1997
From: moderator At: 152.163.205.217
PTW: We don't really know why, however the phenomenon is well documented in sedentary men. It may have to do with declining metabolic rate, or changes in hormone levels. For example, testosterone or growth hormone. One thing we can rule out is its not due to change in exercise patterns, since the apparent rate of weight gain was the same in men running over 40 miles per week, as in men running less than 10 miles per week.
MsgId: *breakthrough(33)
Date: Wed Oct 15 22:38:59 EDT 1997
From: moderator At: 152.163.205.217
Is it the same for women?
MsgId: *breakthrough(34)
Date: Wed Oct 15 22:40:30 EDT 1997
From: moderator At: 152.163.205.217
PTW: We're looking at women now. We have separated the men and the women in looking at these questions, because we know the type of weight gain is going to be different, with men tending to gain weight in their gut, whereas women tend to gain weight in their hips and thighs. We also think that there are important life events in women, such as the weight retention after pregnancy, and menopause, that require these issues to be examined separately from men.A second intriguing result we've observed in our runners, is that the more you run, the less the food you eat seems to affect your weight. That is, among low mileage runners, we see men who consume more meat and less fruits, are heavier. However among high mileage runners, we see the impact of their diet on weight is much less.
Now we are planning studies to try and understand why this is true. Because of the large number of runners in our surveys, we can actually find identical twins in which one is a runner and the other is sedentary, and enter them into the study where they will eat different diets. The beauty of this experiment is that the two twins are genetically identical, and the differences we observe should be due to their physical activity.
MsgId: *breakthrough(38)
Date: Wed Oct 15 22:47:08 EDT 1997
From: moderator At: 152.163.205.217
If your data is so striking, why aren't people who are sedentary warned more strongly about the danger?
MsgId: *breakthrough(39)
Date: Wed Oct 15 22:49:44 EDT 1997
From: moderator At: 152.163.205.217
PTW: We believe that there's been a fundamental confusion in distinguishing physical activity from physical fitness. When we look at all the studies that measure physical activity, we find that the improvements in physical activity accrue in a fairly linear fashion. When we look at the studies that measured physical fitness, we see that the biggest drop in heart disease risk occurs in going from the least fit category to categories that are somewhat more fit. Thus if you confuse the studies, and you were to say that the people's differences in physical fitness were due to their physical activity, then you would reach the same conclusion that the government reached. However, among sedentary people, differences in physical fitness seems to have much more to do with their genetics, than their physical activity. Thus I believe that the governnment's physical activity guidelines have mistaken our genes for our walking shorts.
MsgId: *breakthrough(42)
Date: Wed Oct 15 22:54:14 EDT 1997
From: moderator At: 152.163.205.217
What does that mean for the person who feels that their natural inclination is to watch T.V., not run?
MsgId: *breakthrough(43)
Date: Wed Oct 15 22:55:39 EDT 1997
From: moderator At: 152.163.205.217
PTW: Again, we think that there are some benefits to any exerise or physical activity added to ones life. But the greater the intensity and the greater the amount of the exercise, the greater the health benefit. Thus, the health benefits of exerise is very much like money, and when do you think you have too much?
MsgId: *breakthrough(44)
Date: Wed Oct 15 22:56:38 EDT 1997
From: moderator At: 152.163.205.217
Where are you taking these studies now? Are you going to do more studies?
MsgId: *breakthrough(45)
Date: Wed Oct 15 22:58:29 EDT 1997
From: moderator At: 152.163.205.217
PTW: By launching our studies on the internet, we intend to study all aspects of life style. These include not only physical activity, but diet, prescription drugs, non-traditional medicine -- all aspects of life style. We think that a better understanding of how these factors interrelate could point the direction to achieving optimal health. The Internet will allow us to study millions of people internationally, at minimal cost.We believe that each person is engaged in their own personal experiment, in which the choices that they make will affect their health. We believe that the accumulation of all these experiments can lead the direction to optimal health. Everyone of course is already engaged in their personal experiment. And those interested in contributing to the collective knowledge from all these experiences can contact us at (PTWilliams@LBL.gov).
MsgId: *breakthrough(48)
Date: Wed Oct 15 23:06:36 EDT 1997
From: moderator At: 152.163.194.219
Thank you for joining me tonight on Breakthrough Medicine. Its been great talking with you.
MsgId: *breakthrough(49)
Date: Wed Oct 15 23:07:09 EDT 1997
From: moderator At: 152.163.194.219
PTW: Goodnight.
MsgId: *breakthrough(50)
Date: Wed Oct 15 23:16:10 EDT 1997
From: moderator At: 152.163.194.219
Please join me next week when I speak with Bruce Lehnert, Ph.D., on radiation's effect on DNA.
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