Stepping up your cardiometabolic health

Do those steps around the house contribute to cardiometabolic health?  Can we count those steps around the supermarket as contributing to a step count that will have cardiovascular benefits? Not all steps are created equal so how can we use this to your advantage?  Take a walk with me through this article and let’s find some answers and how we might supercharge your steps to improve your cardiometabolic health.

The Problem 

We all know that there is a global obesity problem and it is now commonplace for obesity to be the leading factor in death, instead of people being underweight and dying from starvation (World  Health Organisation, 2020). Physical inactivity and long periods spent sitting are strongly associated with an increase in the prevalence of obesity and cardio-metabolic disease. Physical activity therefore has become vital for prevention, management and recovery from a host of cardio-metabolic related diseases.

So, what are the barriers to physical activity? The most referred to barriers have been reported as lack of time, lack of motivation, and lack of transportation to exercise in friendly places. Obese populations have cited a lack of perceived sporting ability and embarrassment.

Walking would seem the answer to many of these barriers, such as a lack of transportation, money and perceived sporting ability. However, lack of motivation and particularly time which were the predominant barriers are hard to overcome. One solution is to increase the metabolic cost of walking as a means of addressing time issues.  In this article you will read about ways to supercharge your walking, which may in turn be a way to improve motivation for walking due to the decrease in the time required to achieve greater metabolic cost and/or cardiovascular benefits.

The Solution: Physical Activity Guidelines
So, what are appropriate physical activity guidelines? The American College of Sport Medicine (ACSM) guidelines suggest that adults conduct 150 to 300 minutes of physical activity each week at a moderateintensity, or 75 to 150 minutes of vigorous physical activity. The ACSM also suggested the addition of two days of strengthening activities each week, so don’t forget to hit the gym. Let’s go with these recommendations in terms of walking.

Walking and Walking Intensity

Walking is the predominant form of exercise undertaken throughout the world regardless of gender (Dannenberg, Keller, Wilson, & Castelli, 1989; Tudor-Locke et al., 2008); therefore walking is the most common form of exercise in the world and is used for sport, recreation and transportation. But how do we know that walking bestows health benefits?  Is there a certain threshold volume or intensity needed? If so, how do we measure this?

Step counting has traditionally been used to track distance and brought about the implementation of pedometers. The first of these were found in Japan and were named Manpo Kei.  Tudor-Locke et al. (2008) noted that some pedometers do not track steps below certain velocities of movement. Furthermore, they suggested that the Japanese do not only track step counts but also place a great emphasis on the concept of ‘healthy steps’. 

Pedometers have been criticised for their inability to provide a metric for intensity, however, Scruggs et al. (2003) introduced the concept of steps per minute as a guide to walking intensity, which allows “step counters” to track intensity. As you can see from the previously mentioned ACSM guidelines the terms ‘moderate’ and ‘vigorous’ have been used when prescribing physical activity. However, the term moderate or vigorous can mean one thing to one person and something different to another, so let’s drill down a little. Wang et al. (2013) found that an average of 105 steps per minute was equivalent to a desired step rate for moderate intensity physical activity. These findings are similar with other researchers that have determined 100 steps per minute to be the optimal lower end step count per minute to be classified as moderate intensity (Marshall et al., 2009; Tudor-Locke et al., 2005).

Additionally Wang et al. (2013) reported that 130 steps is likely a good goal for vigorous intensity walking.  In the table I’ve shown how you can use a treadmill to work through what treadmill speeds correlate to steps per minute and for this individual the breakpoint between moderate and vigorous walking is 6.10 km/h or 3.8 m/h. However, you don’t need a treadmill to work this out, simply use your watch, find a flat walk and see what your natural cadence is per minute by counting your steps, and find that cadence that corresponds to moderate (>100 steps per week) or vigorous (> 130 steps per minute) physical activity.

If you have a smartwatch and phone, then this technology will be able to track your intensity also. The device monitors your heart rate and classifies it into different zones based on your maximum heart rate. Moderate intensity is typically associated with 50-70% of your maximum heart rate, whereas vigorous intensity is associated with 70-85% of your maximum heart rate. So the phone tracks how many minutes you walk/work at each intensity.  In the figure you can see the screenshot of a smartphone 7 day summary of how this person is tracking in terms of achieving their 150 to 300 minutes of moderate intensity (> 100 steps/min or 50-70% max HR zone) or 75 to 150 minutes of vigorous physical (> 130 steps/min or 70-85% of your max HR zone ). In this example, they have to complete 90 moderate intensity or 45 vigorous intensity minutes of walking to achieve the ACSM recommended guidelines. 

Figure 1: Smartphone screenshot displaying intensity minutes.

Increasing the Metabolic cost of Walking

Given that researchers have shown a substantial increase in obesity and metabolic disease throughout the world, perhaps it is prudent to look further into increasing the energy cost of walking, particularly when it is well documented that people lack the time for exercise. Therefore, it would be useful to increase the metabolic cost and cardiovascular benefits of walking to reduce the time cost of walking for exercise, and therefore motivate those that otherwise may place it in the too hard/too long basket. So, let’s look at some ways to achieve these ends by looking at methods that don’t and do involve the use of some sort of technology.

Non-Tech Solutions

Stairs and Inclines

Incorporating stairwork and inclines into your walking can supercharge the cardiometabolic cost and cardiovascular benefit of every step you take.  Small behavioural changes such as avoiding elevators and escalators, will benefit your cardiovascular health big time. For example, regular use of stair climbing has been reported to improve cardiovascular fitness, reduce cholesterol level, and decrease body fat (Teh & Aziz, 2002). The caloric cost of stepping up and down a step is 0.16 kcal. 

The added benefits of stair work and inclines are that they can strengthen major muscle groups in the lower body, including the quadriceps, hamstrings, calves, and glutes. Stronger muscles can improve metabolic function, increase resting metabolic rate, and contribute to better overall body composition. If you want to magnify the strength stimulus, try climbing two steps at a time.  Another way to supercharge your step work and increase your strength is lowering yourself slowly as you descend the steps.  This will improve your lengthening or eccentric strength, which might have the added benefit of improving balance and reducing your falls risk. See if you can add a little incline or stair work to your day/week.   

Walking Backwards

I’m a big fan of having a healthy dose of moving backwards in your day, as there is a ton of evidence on how it increases heart rate, oxygen consumption, metabolic cost and reduces stress on the knee joints. One of the things that make backward motion unique, is that there is very little elastic storage and utilisation in moving backwards, which is implicit in walking forwards and makes forward movement much more efficient/economical. By reducing the elastic energy storage and utilisation by walking backwards, the muscular and therefore cardiovascular/cardiometabolic systems are working harder to move your body. Researchers have compared forward motion and backward motion from a mechanical power and muscle [vastus lateralis (VL) and vastus medialis oblique (VMO)] perspective. They concluded that backward motion is a good method that may be useful in clinical conditions that require an increase in knee extensor strength.

In fact, backward motion has been suggested for clinical purposes because it has been proposed to reduce the mechanical stress on the knee, researchers calculating that the compression of the patella against the femur (i.e. patellofemoral joint compressive force) is on average 24% lower during backward motion as compared to forward motion. Give it a go see what you think. If you want to do a double whammy, then walk backwards up a hill. I am pretty sure you will feel this big time in your quads.  

Walking in the Sand

Most of us have walked on a beach and it doesn’t take long to work out that walking on dry sand is a lot harder than walking on wet sand and we soon find ourselves making a beeline to the water’s edge where the harder, wet sand is. Dry sand is an example of an energetically expensive surface for human walking. Basically sand is displaced during push-off and heel strike, the energy we store during hard surface walking is absorbed by the soft sand and therefore not available for the propulsive phase of gait, increasing the energy cost of walking. Researchers have determined that the mechanical work and metabolic cost of walking on dry sand is 2.1 to 2.7 times greater than walking on a firm surface at the same speed (Baxter et al. 2023). So if you walk 1 km on dry sand it would be like doing 2.1 to 2.7 km on wet sand. Or alternatively you can get the same relative workout completed two to three times quicker. In addition, if you are walking barefoot you most likely will get a whole lot of additional strength and flexibility benefits for the lower leg and foot musculature.

Tech Solutions

Trunk Loading - Rucking

A recent fitness phenomenon is “rucking” or walking with a rucksack. School children, travellers and hikers around the world wear backpacks/rucksacks and this may be the most common method for humans to carry loads. When looking to increase the metabolic cost of exercise, trunk loading has been investigated as it is an easy and effective way of increasing load while walking. Research on the metabolic effects of trunk loading is a little conflicting, however, intuitively it makes sense that if you are heavier it is going to require more mechanical and metabolic energy with every step, and also your trunk is working harder to stabilise this additional load. Because of these energetic challenges it has been predicted that metabolic rate increases 7.6 W per additional 1 kg of added load (Huang and Kuo, 2014).

It needs to be noted that researchers have found a strong link between the magnitude of trunk loading and pain, discomfort and exertion. This is most likely due to the backpack/rucksack altering dynamic posture by causing a rearward rotational force around the hip. You can mitigate these eccentric forces on the posture by somehow loading the front side of the body with an equal and opposite load.  Or a better option is the use of vest loaded wearable resistance (https://lilateam.com/), where you attach the Velcro loads to the vest both front and back, to provide neutral loading to the trunk as seen in the figure. The added benefits of the vest loaded wearable resistance is that the compression garment is made of a mesh with micro-perforations that allows cooling, which can be a real problem with rucking. Also, the loading is easily adjusted by simply adding or subtracting the fusiform loads.

Nordic Walking

The birthplace of Nordic walking was Scandinavia around a quarter of a century ago. It was described as a simple, easy and effective way to enhance walking which could be done by almost anyone. Nordic walking involves the use of specially designed poles that the user holds, which assist with walking allowing for heightened engagement of the upper body. Tschentscher et al. (2013) concluded in a systematic review that increases in V0₂ (11-23%) had been found when utilising Nordic walking as compared to standard walking. It was suggested that this range may be attributed to treadmill testing versus field testing, where treadmills seemed to provide much higher increases in V0₂ when compared with normal field based testing. If you want to upsize the cardiometabolic cost and cardiovascular benefits of walking get a pair of poles in your hands.

Limb Loading

Related to Nordic walking is the effects of limb loading on the energy cost of walking. Limb loading occurs when a subject holds weights, or has weights affixed to themselves in some manner. Lower body loading (0.3–8.5 %BM) was found to significantly increase VO2 values (5–11.2 %) during treadmill walking. The more distal the load is placed on the limb the greater the metabolic cost due to the greater mechanical load i.e. increased moment of inertia (moment of inertia = distance of the load from axis of rotation). So, if you want to supersize the metabolic cost of your walks then hold onto some hand weights/dumbbells with full arm swings. You can also attach ankle weights, wear heavier shoes/boots or use wearable resistance and affix loading to the arm (upper and/or lower), thigh or calf. 

Summary

Walking is the most utilised and easily accessible form of exercise in the world, making it a very promising form of physical activity to incorporate into day-to-day life. Researchers have shown that the least-physically-active get the greatest drops in mortality from only small increases in walking. It has been suggested however, that walking intensity must be at least moderate, which is thought to occur at ~100 steps or more per minute. Please note, you should check this step rate against your heart rate (50-70% of predicted heart rate max) to individualise loading to your fitness level.

Increasing the intensity of walking through an increased step rate is a good idea because of the higher metabolic demand, and ease of implementation. Stair and hill work, walking on dry sand and backward walking have also been suggested as ways to increase the metabolic cost of walking.  Finally, the use of load (rucking, Nordics, etc.) have also been suggested as ways to increase the metabolic cost of walking. Increasing the load whilst walking may provide an additional strength training stimulus that increasing the step rate of walking alone does not. The addition of strength adaptations through trunk and or limb loading may further assist with people’s ability to meet public health recommendations, especially now recommendations incorporate both aerobic activity and strength-based activity each week. Additionally, if the energy cost of walking increases enough then the time cost of exercise could drop even further, a desirable outcome for anyone short on time.

References

Baxter, B.A. & Warren, W.H. (2021). A day at the beach: Does visually perceived distance

depend on the energetic cost of walking?  Journal of Vision, 21(12): 13, 1-14.

Dannenberg, A. L., Keller, J. B., Wilson, P. W. F., & Castelli, W. P. (1989). Leisure time physical activity in the framingham offspring study: Description, seasonal variation, and risk factor correlates. American Journal of Epidemiology, 129(1), 76-88.

Huang, T.W.P. & Kuo, A.D. (2014). Mechanics and energetics of load carriage during human walking. Journal of Experimental Biology, 217 (4): 605–613.

Marshall, S. J., Levy, S. S., Tudor-Locke, C. E., Kolkhorst, F. W., Wooten, K. M., Ji, M., . . . Ainsworth, B. E. (2009). Translating Physical Activity Recommendations into a Pedometer-Based Step Goal: 3000 Steps in 30 Minutes. American Journal of Preventive Medicine, 36(5), 410-415.

Scruggs, P. W., Beveridge, S. K., Eisenman, P. A., Watson, D. L., Shultz, B. B., & Ransdell, L. B. (2003). Quantifying physical activity via pedometry in elementary physical education. Medicine and Science in Sports and Exercise, 35(6), 1065-1071.

Teh, K.C. & Aziz, A.R. (2002) Heart rate, oxygen uptake, and energy cost of ascending and descending the stairs. Medicine and Science in Sports and Exercise, 34(4), 695–699.

Tschentscher, M., Niederseer, D., & Niebauer, J. (2013). Health Benefits of Nordic Walking: A Systematic Review. American Journal of Preventive Medicine, 44(1), 76-84.

Tudor-Locke, C., Hatano, Y., Pangrazi, R. P., & Kang, M. (2008). Revisiting "how many steps are enough?". Medicine and Science in Sports and Exercise, 40(7 Suppl), S537-543.

Tudor-Locke, C., Sisson, S. B., Collova, T., Lee, S. M., & Swan, P. D. (2005). Pedometer-Determined Step Count Guidelines for Classifying Walking Intensity in a Young Ostensibly Healthy Population. Canadian Journal of Applied Physiology, 30(6): 666-676

Wang, H., Zhang, Y.-f., Xu, L.-l., & Jiang, C.-m. (2013). Step rate-determined walking intensity and walking recommendation in Chinese young adults: a cross-sectional study. BMJ Open, 3(1), e001801.

World Health Organisation. (2018). Non-Communicable Disease. Retrieved from https://www.who.int/news-room/fact-sheets/detail/noncommunicable-diseases