By Lance C. Dalleck, Ph.D.
There is no question that modern-day life has virtually eliminated the requirement to be physically active. Unlike our Paleolithic ancestors, our survival is not dependent upon our ability to hunt, gather or grow our own food or even build our necessary shelters. With these advances, of course, have come a serious downside—a sedentary, indoor lifestyle that is at the origin of many of the once-rare chronic diseases that are now all too common. Some have suggested that replicating the activity patterns of indigenous humans—to the extent that this is possible and practically achievable in today’s society—could be an effective way to reduce the incidence of these diseases. This article examines this premise and offers practical recommendations for exercise frequency, intensity, duration and mode for realigning our daily physical activities with the classic levels expected within our unchanged Paleolithic genome.
A Genetic Predisposition for Physical Work
For most of the past 2.4 million years, approximately 84,000 generations of our ancestors lived a lifestyle comprised of hunting and gathering (O’Keefe et al., 2011). The existence of hunter-gatherers was characterized by foraging and hunting for food, producing water, building and maintaining clothing and shelter, escaping from predators and enjoying social interaction. Accordingly, over time the human genetic profile gradually adapted through natural selection for individuals to survive and thrive in an environmental climate that demanded large amounts of regular physical work. More recently, from an evolutionary perspective, there have been rapid improvements in technology that have brought about marked reductions in the physical work required as part of daily life. In fact, technological advancements over the past 10,000 years—a period marked by the Agricultural Revolution (the past 350 generations), Industrial Revolution (the past seven generations), and in particular the Digital Age (the past two generations)—have resulted in the elimination of most previously required physical activities (O’Keefe et al., 2010a). For instance, in most Westernized countries, the need to spend a meaningful energy expenditure on obtaining food has become virtually obsolete. Despite the quantum leap in technology during this 10,000-year period, our genetic profile has remained largely unchanged. In reality, it has been estimated that our genome is 98.4 percent similar to what it would have been just prior to the Agricultural Revolution (Eaton, Konner and Shostak, 1988).
Discordance Hypothesis and its
The shortfall between physical-activity levels anticipated by our genetic profile for normal metabolic function, and that which is actually incurred (a premise referred to as the discordance hypothesis), has created an environment ideal for the manifestation of various chronic diseases. In recent times, particularly over the past 100 years, there has been a meteoric and widespread rise in the prevalence of obesity, type 2 diabetes and cardiovascular disease. These conditions, nonexistent-to-rare in the ancient world, are now common throughout modern society (O’Keefe et al., 2010b). Every year since 1900, with the exception of 1918 when there was a worldwide influenza epidemic, cardiovascular disease (CVD) has been the most common cause of death. According to the American Heart Association, 82.6 million American adults (more than one in three) have one or more types of CVD (Lloyd-Jones et al., 2007). Although the prevalence of CVD-related deaths has declined since the 1980s, it remains the leading cause of death in the United States (Roger et al., 2011). In 2007, CVD claimed 813,804 lives, with nearly half (49.9 percent) attributable to coronary artery disease.
Since the advent of the digital age two generations ago, there has been a particularly alarming increase in the prevalence of obesity and type 2 diabetes. For example, in the time period between 1960 and 2000, the prevalence of U.S. adults with class I obesity (BMI between 30.0 and 34.0 kg/m2) increased, on average, by 2.5 percent per year (Booth et al., 2000). 2009 data show that only one state’s population (Colorado) had a prevalence of obesity of less than 20 percent. Thirty-four states were equal to or greater than 25 percent and nine of these (Alabama, Arkansas, Kentucky, Louisiana, Mississippi, Missouri, Oklahoma, Tennessee and West Virginia) had a prevalence equal to or greater than 30 percent (Centers for Disease Control and Prevention, 2012). It has been estimated that nearly 300,000 deaths per year can be attributed to obesity (Booth et al., 2000). In a similar manner to obesity, the prevalence of type 2 diabetes has skyrocketed throughout the digital age. A sixfold increased prevalence of type 2 diabetes occurred between 1958 and 1993. To date, 25.4 million American adults (11.5 percent of the U.S. adult population) have diabetes mellitus. The American Diabetes Association estimates that nearly 200,000 deaths per year are attributable to type 2 diabetes; this number is expected to rise in the future (Booth et al., 2000).
Unfortunately, the elimination of both the need for, and the performance of, regular movement has left our bodies confused and vulnerable to chronic disease (see sidebar, “Discordance Hypothesis and its Clinical Significance”).
What is the solution? Although many approaches are likely necessary, taking a closer look at the physical-activity patterns of our Paleolithic ancestors may yield valuable understanding into what is needed to restore metabolic health. In other words, an examination of our past might provide the answer to a better future.
The Paleolithic Exercise Regimen: Life in the Wilderness
One overarching theme to the Paleolithic lifestyle was that regular physical activity was not optional; it was absolutely mandatory. After all, being both physically active and highly fit in the ancient world was necessary for survival. There are four aspects of the hunter-gatherer routine that provide insight into what is required in modern times in terms of physical activity to combat the development of chronic disease.
Daily Physical Activity
The typical day for a hunter-gatherer was defined by a substantial amount of high-volume, low- to moderate-intensity walking. To acquire water and food frequently required covering long distances over arduous terrain. It has been estimated that the daily distance covered by hunter-gatherers ranged between five and 10 miles. The corresponding energy expenditure for this volume of physical activity is approximately 600 to 1800 calories per day—roughly three to five times higher than that of the typical American today (O’Keefe et al., 2010a). Moreover, because the purpose of daily travel was largely driven by subsistence acquisition, this meant that much of the distance travelled would have also involved carrying heavy loads of food and/or water acquired during the day from the hunting and gathering. This daily level of physical activity was performed by all members of the hunter-gatherer society with the exception of the very young and very old. Interestingly, it has been reported that even women with young children would have walked up to three miles daily, while carrying not only their children, but also food, water and wood (Panter-Brick, 2002).
Primitive Resistance Training
Although a hunter-gatherer never would have lifted a stone with the specific intention of improving muscular strength, this task and other related manual physical demands naturally elicited, as a by-product, high levels of muscular fitness. At the conclusion of a successful hunt, game would have been carried back (frequently over long distances) to camp. Foraging for other food, such as nuts and berries, demanded much bending, climbing, digging and lifting. And in a similar manner to hunting, it was then a regular requirement for gathered food to be carried long distances from the location of collection to encampment. Another requisite physical chore that contributed to muscular fitness for hunter-gatherers was the construction and maintenance of living quarters, which required regular repair and upkeep. Furthermore, hunter-gatherers were also required to construct their own tools for building (O’Keefe et al., 2011).
While the majority of travel involved in hunting and gathering consisted of walking long distances at a low-to-moderate intensity, it was also common for there to be periodic segments of more high-intensity activity. For instance, hunting and stalking animals has been equated to the modern activity of interval training; however, this would have likely been restricted to a few times per week as the meat from a successful hunt would have lasted several days (O’Keefe et al., 2010b).
Two additional points of interest we can discern from the hunter-gatherer lifestyle that are relevant to recapturing fitness in the modern era include the general pattern and variety of activity in primitive times. The wide array of daily tasks required in the hunter-gatherer lifestyle ensured high levels of physical fitness in all areas, including cardiorespiratory fitness, muscular fitness and flexibility. It is unlikely that a hunter-gatherer would have only been part of the hunt (i.e., the aerobic activities), and would not also participate in transporting the game (i.e., the muscular fitness activities) back to camp. Likewise, hunter-gatherers would not have participated in lifting food, water and/or wood (i.e., muscular fitness activities), without also travelling significant distances to locate these items and then carried them back to camp (i.e., aerobic fitness activities).
All individuals participated in all activities of daily life, thus ensuring high levels of comprehensive physical fitness (O’Keefe et al., 2011).
Another intriguing feature of the Paleolithic lifestyle was that a sequence of physically demanding days would have been followed by a rest day. A laborious, multiday hunt that involved travel over many miles to locate game, and the subsequent task of carrying the heavy loads from a successful hunt back to camp, would be followed by relatively easy days of performing less-demanding tasks around camp. It is important to note, however, that a hunter-gatherer simply did not take the entire day off and do nothing—an easy day still involved much physical activity and might consist of maintenance work on shelters, building/repairing hunting tools and social activities such as dancing. The natural periodization of Paleolithic exercise (hard days followed by recovery days) is comparable to the practice followed by many modern-day athletes in their training programs.
Logically, the proposition of a Paleolithic exercise program seems to have considerable merit; however, before fitness professionals give too much thought to adopting this strategy in training their clientele, a responsible first step is to explore the scientific rationale for such an approach.
Does Current Research Support the Premise of a Paleolithic Exercise Program?
Hallmark features of the primitive lifestyle included regular walking over lengthy distances with episodic bursts of higher-intensity sprinting, as well as high levels of muscular work characterized by much bending, climbing, digging, lifting and various other forms of physical labor. Findings from current research lend credence to this “activity pattern” way of life. In fact, daily energy expenditure from physical activity is one of the most powerful predictors of long-term health and survival (O’Keefe et al., 2010b). Moreover, research has demonstrated that a strong dose-response relationship exists between exercise volume (performed at low-to-moderate intensity) and the accrual of numerous health benefits, including improvements in cardiorespiratory fitness, body composition, lipid profile and insulin sensitivity (American College of Sports Medicine, 2010). Recent research has revealed that quick and impressive improvements in cardiorespiratory fitness can be achieved with high-intensity interval training. For instance, one investigation showed a 20 percent improvement in cardiorespiratory fitness after only six weeks of interval training (Gormley et al., 2008). An optimal level of cardiorespiratory fitness is arguably the most important factor for cardiovascular health, as it has been shown that low cardiorespiratory fitness accounts for more deaths in both men and women than any other cardiovascular disease risk factor, including smoking, obesity, hypertension and hypercholesterolemia (Blair, 2009). Research also confirms the importance of performing sufficient resistance-training activities to complement regular aerobic activity. In fact, many studies show an augmented training adaptation when aerobic and resistance training are combined compared to aerobic training alone (Garber et al., 2011).
In summary, it appears that not only is there an instinctive rationale to support mimicking the activities of our ancestors, but equally important, there is also a strong scientific basis underpinning the principles of a Paleolithic exercise program. We’ll now turn our attention to various schemes you can employ to put a Paleolithic exercise program into everyday practice with your clientele.
A Paleolithic Exercise Program for the 21st Century
First, it is important to acknowledge that even with highly committed clients, the technological reality of the world today will make it extremely challenging for them to achieve similar physical activity and fitness levels to those of their Paleolithic predecessors. This realization ensures appropriate expectations for both you and your clients.
Figure 1. Examples of Modern-day Activities That Mimic Paleolithic Activities
The purpose of engaging in Paleolithic activities is to bring alignment between what our bodies genetically expect and require, in terms of physical activity, and that which they actually achieve.
(trails and grass)
(fields and hills)
|Hunting, stalking animals
mowing the lawn
|Gathering nuts and berries
Let’s now examine the Paleolithic exercise recommendations for frequency, intensity, duration and mode (O’Keefe et al., 2010a, 2010b, 2011). The primary aim of the Paleolithic exercise program is to realign our daily physical activities with the classic levels expected within our unchanged Paleolithic genome. Figure 1 illustrates how the following recommendations accomplish this goal.
- We are genetically adapted to daily, high volumes of low- to moderate-intensity walking. Depending on the individual client and his or her health history, three to 10 miles per day can be recommended. Ideally, the more walking that can be done on natural surfaces and in natural settings, the better. We were designed to be outside and on grass or dirt.
- Interval training should be performed one or two nonconsecutive days per week. These sessions should consist of intermittent bouts of moderate- to high-intensity exercise interspersed with low-intensity exercise.
- Our bodies can genetically accommodate regular and diverse resistance exercises. Accordingly, resistance training should be performed at least two to three days per week for approximately 30 minutes per session. Theoretically, functional-training exercises, as compared to machine-based exercises, are more aligned to the daily activities of our ancestors, and for this reason might be more preferable. Another advantage to functional training is that there is virtually a limitless assortment of exercises from which to choose. Nevertheless, any form of resistance training is better than none.
- In the primitive world, when it came to the relationship between physical activity and the acquisition of food and water, people rarely got something for nothing. Simply put, the procurement of nutrition required energy expenditure. Although this scenario will never be recreated in its entirety, encouraging clients to practice a few of the following simple measures will contribute to an increase in physical activity:
- Plant and maintain your own garden.
- Go fishing or hunting.
- Park in the farthest parking space from the grocery store; if possible, bike or walk to the grocery store. Carry your groceries instead of using the cart.
- When getting a drink of water in your home or at work, walk to the farthest source; if possible, make sure it requires going up and down a flight of stairs.
- Even when hunter-gatherers were enjoying an easy day, they still participated in activities, such as dancing, that elicited significant energy expenditure. Encourage your clients to select weekly social and/or recreational activities that will require a meaningful amount of physical exertion (e.g., dancing and golfing).
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Roger, V.L. et al. (2011). Heart disease and stroke statistics, 2011 update: A report from the American Heart Association. Circulation, 123, e18–e209.
Lance C. Dalleck, Ph.D., is academic coordinator of the cardiac rehabilitation postgraduate program at the University of Auckland in New Zealand. His research interests include improving exercise performance and health outcomes through evidence-based practice, quantifying the energy expenditure of outdoor and non-traditional types of physical activity, and studying historical perspectives in health, fitness and exercise physiology.