We have all been told that exercise is good for us and should be incorporated into our weekly routine to help stay healthy. But why is that? Why does lifting some dense hexagonal object help? Also, with all of the different types of exercise on offer it can get rather confusing to know what to choose Physiotherapy, Pilates, yoga, hydrotherapy, commercial gym, group classes, walking around the block to name a few.

The purpose of this article is to give some insight of the reasons why exercise is important, what kind should be done as you get older, and to answer some of those questions you might have regarding this topic. As we get older there are many changes that occur, the purpose of this article will focus on the changes of bone, muscle and the cardiovascular system.

Benefits of exercise on bone density

Our bones are made up of a thick outer layer, and a thinner ‘honeycomb’-like structure on the inside which helps redistribute force when it’s loaded (when walking/jumping etc). There is a continual cycle of bone growth and resorption throughout our life which is influenced by our activity levels + hormones. However, as we age, if not appropriately loaded through activity or with hormonal changes in life (such as menopause), can result in bone breakdown greater then bone growth and lead to loss of bone mineral density (BMD).

Adults above the age of 60 can have around 2-5% of BMD loss per year, with post-menopausal women being more susceptible. Meaning the outer walls get thinner and the honeycomb structure has larger holes, which can increase the risk of fractures + breaks (also referred to as osteopenia + osteoporosis).

Exercise has been proven to be an effective means to stimulate bone osteogenesis (bone formation). This can help maintain, and sometimes reduce BMD loss in adults. According to Wolff’s law, the remodelling of bone occurs in response to physical stresses, meaning a certain mechanical intensity must be reached in order to be effective (i.e. walking does not produce enough ground reaction force to stimulate bone formation).

An intensity greater than common daily activity is required, and progressive resistance training has been the preferred method to achieve this. Research has recommended a training intensity of 70-90% 1RM, for 2-3 sets of 8-12 repetitions. 3-5 times per week for around 45-70 mins per session.

Benefits of exercise on muscles

Skeletal muscle attaches to bones and their main function is to contract (shorten) to produce movement of our skeleton. These muscles are contracted voluntarily with direct control from our nervous system, we can vary our level of contraction to produce powerful movements (lifting a heavy box), fine movements (drawing with a pencil) or fast movements (clapping). Skeletal muscle atrophy (loss) is often considered a hallmark of ageing and physical inactivity. Sarcopenia, or the decline of skeletal muscle tissue with age, is one of the most important causes of functional decline and loss of independence in older adults (more common in people over 50). A loss of muscle is concerning as it’s important role in movement, balance, falls risk reduction, functional independence and overall quality of life.

The ability to safely perform activities of daily living such as getting up from a chair, climbing a set of stairs, carrying your groceries etc. is all dictated by your ability to generate enough force to perform these movements. Sarcopenia is characterised by a decline in the size and number of muscle fibres, and infiltration of fatty tissue into the skeletal muscle.

After the age of 50, adults lose on average 3% of their muscle strength every year, and around 1% of muscle size every year. Disuse is one of the strongest triggers of sarcopenia, as well as diet, inflammation + stress also contributing. Focusing on combating disuse, resistance training has been shown to have long term effects on muscle hypertrophy (increase in size). Assisting in the prevention, as well as even being able to reverse muscle loss in older adults. This occurs via the activation of satellite cells in response to mechanical tension. These satellite cells are responsible for muscle regeneration and repair.

Benefits of exercise on cardiovascular fitness

Our cardiovascular system consists of our heart, veins, arteries and capillaries. The main purpose of this system starts with the right side of the heart pumping blood to the lunge to pick up oxygen, and the left side of the heart to receive oxygen rich blood from the lungs and pump it to the rest of the body. The heart is a cardiac muscle, and much like our skeletal muscles, it can weaken over time. Especially if you are sedentary. Our cardiovascular function (CVF) declines as we age and accelerates after 45 years of age.

Key factors to help improve this fitness is to maintain a low BMI, be physically active and reduce/cease smoking across the life span. Performing aerobic activity can help decrease cardiovascular disease. Diseases such as hypertension, coronary artery disease, diabetes, metabolic syndrome and atherosclerosis. Cardiovascular training is defined as aerobic training, meaning exercising “with oxygen”. So your breathing and heart rate will increase during aerobic activities. Aerobic exercise training in older people has been shown to decrease resting heart rate, systolic and diastolic blood pressure and improve your stroke volume (amount of blood ejected by the heart on each heartbeat).

To attain a high level of cardiorespiratory fitness, it is recommended to be physically active for 6 months or longer. Individual sessions in general should be around 30 minutes in duration and be slowly and gradually increased in intensity, a few guidelines on intensity have been described such as working at a 5-6 on a Rate of perceived exertion scale (RPE) or ~65% max heart rate (This can be monitored with a smart watch).

Putting this all together

In general, the Australian government department of health and aged care recommends adults over the age of 65 partake in 30 minutes of moderate intensity physical activity on most, preferably all days of the week. To include exercises which challenge strength, flexibility, balance and aerobic (cardiovascular) fitness. In Australia in 2020-2021, around 6-in-10 (58.2%) of people above the age of 65 did not meet these minimum recommendations. Here at Wilston Physiotherapy & Massage, our practitioners can tailor specific workouts to suit your needs, capabilities and experience to help you reap all of the benefits that can be attained from exercise. A assessment is performed to understand your medical history, exercise + injury history, to determine what the best exercises and dosage will work best for you.

Exercise Guidelines for older Australians –
Effect of Weighted Exercises on Bone Mineral Density in Post Menopausal Women A Systematic Review –