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AGING MUSCLES – MOVE THEM OR LOSE THEM

One thing we can't escape as we age is "sarcopenia", the degenerative loss of skeletal muscle mass, quality and strength brought about by aging. After age thirty our muscles start to deteriorate. After age forty we lose, on average, eight percent of our muscle mass every decade, and this rate of deterioration accelerates after age sixty.


Even the most active of people will feel the effects of sarcopenia and end up with less skeletal muscle mass, lower muscle strength and/or inhibited physical performance. But while sarcopenia has the potential to curtail quality of life and increase the risk of physical disability there are some things to keep in mind when considering it.


1) While the magnitude varies substantially across individuals, some degree of muscle mass loss impacts everyone as they get older.


2) Due to a lower starting muscle mass and energy intake, prevalence estimates are greater in women compared with men.


3) Sarcopenia is not only muscle mass loss, it is also strength loss, and the rate of its onset is not linear. It can occur in specific muscles as a consequence of inactivity after an injury or as a response to bed rest induced by disease, for example.


The underlying causes of sarcopenia are multifactorial, interconnected and complex. A decline in physical activity, common among older people, is only one reason sarcopenia happens. Other contributing factors include poor nutrition, elevated oxidative stress, excessive protein breakdown coupled with decreased protein synthesis, hormonal changes, chronic illness and chronic inflammation. But even though the onset of sarcopenia is somewhat inevitable, other factors that contribute to it--like a decline in physical activity--are not.


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As we age it is natural for our aerobic capacity to decline and for us to gradually lose muscle mass and strength. And it is true that this will negatively impact our health and, in later life, our ability to perform acts of daily living. But this decline does not have to result in us moving less.


Think back to your youth. Do you move as much now as you did then? Most don't. Why is that? What would happen if we started paying attention to this fact and built a lifestyle that forces us to be more active on a daily basis? What would happen if we shifted our focus onto the things we can control and broke some of the barriers that prevent us becoming and staying more active? More importantly, why should we?


Collectively--at the international and national level--the aging of the world's population is one of the most pressing issues. An increasing life expectancy coupled with a movement towards more sedentary lifestyles and poorer dietary patterns has implications for governments, their finances and the global markets they are a part of.


Individually, efforts to roll back the onset of aging and all that it brings result in greater physical and mental health. That means more energy and more ability to do the things that you love, with the people you love, for a longer period of time.


The obvious question at this point is how does one go about slowing down the process of aging and, in particular, prevent the onset of sarcopenia? The answer is threefold: increase protein consumption, increase baseline activity, and engage in resistance and high-intensity interval training.


1) PROTEIN CONSUMPTION


One of the key elements in maintaining musculoskeletal health is sustaining long term adaptations to both resistance exercise and aerobic exercise. These adaptations are greatly supported by an adequate intake of dietary protein.


Currently, the Recommended Dietary Allowance (RDA) for protein is 0.8 grams of protein per kilogram of body weight, regardless of age and sex. However, these recommendations represent the minimum daily protein intake, not necessarily the optimal. And given the fact that older adults experience muscle mass decline as they age, the protein RDA is likely insufficient for healthy older adults looking to maintain skeletal muscle mass and function.


In fact, a growing body of research indicates that protein intakes well above the current Recommended Dietary Allowance may help prevent age-related sarcopenia. According to these new studies, intakes in the range of at least 1.2 to 1.6 grams of protein per kilogram of body weight of high-quality protein is a more ideal target for achieving optimal health outcomes in aging adults. Higher protein diets also improve satiety and might contribute to weight management by helping to regulate appetite.


(It is important to mention that these recommendations are not suitable for critically ill patients and those suffering from certain conditions, like kidney problems.)


2) BASELINE ACTIVITY


Physical activity (any bodily movement that involves skeletal muscle contraction and increases energy expenditure) and exercise (physical activity that is planned, structured and repetitive) have both been shown to slow the onset of many chronic diseases and mitigate the risks of aging. To promote this fact and encourage physical exercise throughout our life, the WHO and governments around the world issue guidelines and recommendations.


Traditionally, these guidelines have emphasized aerobic exercise. Part of this might be due to the fact that there is greater volume of data and research available for aerobic exercise as opposed to resistance exercise. The other factor might be related to the misconception that resistance training is riskier, less safe and requires special equipment.


Current recommendations for adults are: 150 minutes of moderate-intensity or at least 75 minutes of vigorous-intensity aerobic physical activity per week, in bouts of 10 min or more, at least 5 days per week. For additional health benefits, older adults should increase this to 300 minutes of moderate-intensity or at least 150 minutes of vigorous-intensity aerobic physical activity per week. Muscle-strengthening activities, involving major muscle groups, should be done on 2 or more days a week.


The point of these recommendations is to, at the least, maintain a minimum level of activity throughout our lives. At best, we can strive to continually challenge ourselves as we age and increase our baseline of physical activity. That doesn't only mean engaging in a greater number of scheduled and structured gym sessions--exercise, in other words. It also means upping our physical activity. Taking the stairs instead of the elevator, cycling or walking when we could drive, and sitting on the floor when we could sit on the sofa. It all counts, after all.


3) RESISTANCE AND HIIT TRAINING


As mentioned above, most guidelines tend to emphasis aerobic exercise. But since resistance training has been widely used to enhance and maintain muscle mass and strength in a variety of populations, many researchers argue that guidelines should give more prominence to advise about exactly how much and what type of resistance training is needed.


The arguments of these researchers are supported by number of studies, all of which have shed additional light on the benefits of resistance training. Increased muscle mass, improved cardiovascular health and cardiorespiratory fitness, more efficient regulation of blood sugar, protection against the insulin resistance associated with Type 2 diabetes, and greater bone mineral density are all effects correlated with regular resistance training.


Despite these studies there seem to be some misconceptions regarding resistance training. Some think that is complicated and that it has to involve very heavy weights. That it is painful and only for the hardcore. As with any other type of exercise it has to be sufficiently challenging, and there should be some discomfort, but there is more than one approach.


In a traditional weight training program, a trainee’s first task could be to find the heaviest amount of weight they can lift one time using a given exercise. This one-rep max could then be used as a guide to construct the rest of the program, whose main part consists of lifting 80 to 90 percent of that amount eight to ten times across sets, until fatigue sets in. While this approach can be effective for many, it can also be uncomfortable. Another approach (one of the many out there) could be to utilize the same exercises but at lighter weights for more repetitions.


Regardless of the specific resistance training program followed, basic principles apply. Proper technique is crucial for injury prevention and longevity of training, so is regular assessment and adequate recovery. Difficulty should progressively increase too--via changes in repetitions, sets, weights, and tempo. If you're not confident and lacking experience, it may be a good idea to have someone walk you through the basics.


Another form of exercise that is increasingly being incorporated into "official" guidelines, alongside resistance training, is high-intensity interval training, or HIIT.


Aerobic exercise has been more commonly associated with cardiovascular fitness and oxidative capacity, whereas resistance exercise has been linked to skeletal muscle mass and strength. However, aerobic-based physical activity may be considered an important, and often underappreciated, intervention targeted at overcoming age-related muscle mass and strength loss.


Activities like cycling have been shown to increase muscle volume and muscle power in adults and results often vary depending on variables like exercise intensity and training history and/or age. Specifically, studies have shown that HIIT has the capacity to stimulate increases in muscle mass comparable to some resistance-based exercise. Low-intensity aerobic exercise is performed at a constant workload. In contrast, HIIT consists of brief, intermittent bursts of vigorous activity followed by periods of lower intensity or rest. These bursts of activity are thought to be a key factor in stimulating muscle protein synthesis.


One of the reasons why HIIT has not been more widely recommended for older adults is related to the common misconception that HIIT can be riskier for individuals with cardiac issues and other medical conditions. But evidence shows that older individuals are not at greater risk when performing HIIT compared to low-intensity aerobic exercises.


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For aging populations, making dietary changes might be easier than making changes to physical activity and exercise levels, and when it comes to the latter there are some commonly cited barriers. For example:


- Risk of injury.

- Lack of access.

- Not fitting in.

- Low confidence.

- Little time.

- Lack of immediate results.


However, all of these barriers can be overcome.


- Risk of injury. It takes time for the body to adjust to new physical stimuli. If you start slow and train with patience, you'll lower the chances of injury. If you have existing conditions or specific worries, consult a physician.


- Lack of access. Simple routines can be done almost anywhere. You don't need thousand-dollar equipment. Your own bodyweight and a few square meters of space can be enough.


- Not fitting in. Gyms can be intimidating, as can clubs. If you can, take a friend with you, and if you can't, just take a look at the thousands of people jumping into new activities and discovering that the people that already do them are way more friendly and accommodating than they thought.


- Low confidence. Feeling old and unattractive is a common barrier to increasing physical activity, especially for women. But becoming more active is not about looking good. It is about feeling healthier, stronger and more energetic. If you're a beginner, some time alone at home familiarizing yourself with common exercises can be good preparation for visiting a gym or leisure center.


- Little time. We make time for what matters to us. If a person thinks their health and fitness is important, they'll find some time in their schedule. It doesn't have to be hours a day. Starting with ten minutes in the morning is better than nothing.


- Lack of immediate results. With age comes a slowing down of adaptation. Visible results mostly come after several weeks of consistent effort, not days. My advice when starting something new? Give yourself a minimum period of time --6-10 weeks at least-- before you decide whether something is "working" or not.


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Maintaining an active lifestyle is a priority for many recreational athletes like me. Yet when we reach “middle-age” many of us get curious and anxious about what’s coming. A quick search concerning the effects of aging turns up some scary results and leaves a person feeling very worried. But should we just accept that getting older means a steep decline in performance, a more fatigued body and higher risks of injury and illness? Not necessarily.


We don’t have to be young in order to be active and engage in exercise. We have all seen the stories of the super-fit seniors that break age group records in swimming, running and many other sports. These stories make good headlines but we might feel that we are nowhere close to either their age or their physical shape, but what is great about these stories is that they highlight the fact that getting older doesn’t have to mean becoming sedentary.


Even if you have neglected your health in recent years and are now middle-aged, it is not too late. Everyone can benefit from eating better and exercising more, regardless of age, and while increasing levels of protein, activity and exercise won’t stop aging, it will slow it, and make life a lot more enjoyable in the process.