Physical activity represents a cornerstone in the primary prevention of at least 35 chronic conditions. However, over the past two decades, considerable knowledge has accumulated concerning the significance of exercise as the first-line treatment of several chronic diseases.
A review of multiple studies was performed by B.K. Pedersen and B. Saltin, which included the latest information on evidence of prescribing exercise as therapy in multiple chronic conditions. We are going to review some of them.
A study comprising 156 participants over the age of 50 with severe depression randomized the patients to 4 months of aerobic exercise, 4 months of treatment with antidepressants, and 4 months of treatment with both medication and exercise. Each session of exercise began with 10 min of warm-up, 30 min of cycling or jogging, and 5 min of cool down.
The medical treatment had a quicker initial effect, but after 4 months, there was no difference between the three groups for symptoms of depression. But that changed in the 10-month follow-ups, where participants showed significantly lower levels of depression symptoms and fewer incidences of relapse in the exercise groups.
The positive effect of exercise on depression is believed to be multifactorial. One proposed mechanism is that exercise stimulates the growth of new nerve cells and release of proteins known to improve health and survival of nerve cells. It is possible that physical activity has a direct positive effect on the hippocampus, an area with reduced volume in patients with depression.
In several randomized controlled trials involving subjects with a normal or increased level of anxiety who do not meet the criteria for psychiatric diagnosis, it has been shown that physical activity can reduce symptoms of anxiety and tension. It is uncertain, however, whether it has a long-lasting effect.
A meta-analysis from 2010 comprising 40 studies concludes that physical training reduces symptoms of anxiety in people with chronic illnesses, including cardiovascular disease, fibromyalgia, multiple sclerosis, mental disorders, cancer, and chronic obstructive pulmonary disease.
In a meta-analysis from 2015, psychiatric symptoms were significantly reduced by interventions using around 90 minutes of moderate-to-vigorous exercise per week.
People with schizophrenia often have accompanying symptoms, such as anxiety and stress, and physical activity can help alleviate these symptoms. In some cases, physical activity can provide an infrastructure and an environment that support social interactions and thus help the patients to establish networks, counteracting the tendency toward social withdrawal.
According to a Cochrane review 2013, there is promising evidence that exercise programs can have a significant impact on improving the ability to perform activities of daily living (ADL) and possibly improving cognition in people with dementia.
One study (Kemoun et al., 2010) included 31 elderly subjects with dementia randomized to a training group or a control group. The training program comprised 15 weeks of 1 h of physical activity three times a week. After 15 weeks, the training group had improved their cognitive function, while the control group experienced a decline in cognitive function.
Baker et al. (2010) included 33 middle-aged and older people with mild cognitive impairment who were randomized to either a control group that did stretching and balance exercises or to a training group that did intensive aerobic training 45–60 min a day, 4 days a week for up to 6 months. There was a significant positive effect on the participants’ cognitive function.
A 2010 Cochrane Review (Mehrholz et al., 2010) assessed the significance of treadmill training. The analysis included eight trials involving 203 participants. Treadmill training was found to increase walking speed, stride, and walking distance.
A prospective crossover study investigated the effects of 4 weeks of treadmill training with partial body weight support and general physiotherapy (n = 10). The study found that aerobic exercise, unlike the unspecific physiotherapy, improved the patients’ ability to manage their daily lives (ADL) and their muscle function.
A Cochrane Review from 2006 (Shaw et al., 2006) comprising 3476 overweight or obese individuals studied 41 randomized controlled trials and concluded that physical activity alone induced significant weight loss, while physical activity combined with a restricted diet and dietary counseling was more effective. High-intensity physical activity was more effective than moderate activity.
The Cochrane Review showed that physical training for overweight and obese adults had positive effects on both body weight and risk factors for cardiovascular disease.
For weight loss, a large volume of moderately intense aerobic exercise is recommended, preferably in combination with strength training. Because physical fitness has an independent impact on preventing diseases associated with obesity, it is recommended that moderate physical activity be combined with activities that build fitness in the form of high-intensity physical activity.
An American study randomized 3234 people with pathological glucose tolerance to either treatment with metformin or a lifestyle program involving moderate physical activity in the form of at least 150 min of brisk walking a week and a reduced-calorie diet or no intervention.
The subjects were monitored over 2.8 years (Knowler et al., 2002). The lifestyle intervention group had a 58% lower risk of contracting type 2 diabetes, while the metformin treatment only reduced the risk of diabetes by 31%.
Visceral fat constitutes an independent risk factor for developing heart disease. Increasing physical activity to 60 min/day over 3 months has been found to reduce visceral fat volume by about 30%.
Resistance and aerobic exercises can both be recommended as effective treatments for people with metabolic syndrome.
Type 2 diabetes
The positive gains from physical exercise for patients with type 2 diabetes are very well documented.
A 2006 Cochrane Review, which includes 14 randomized controlled trials with a total of 377 patients with type 2 diabetes, compares the independent effect of training with no training (Thomas et al., 2006).
The training interventions were 8–10 months in length and consisted of progressive aerobic training, strength training, or a combination of the two, with typically three training sessions per week.
The training interventions showed a significant improvement in glycemic control in the form of a reduction in HbA1c of 0.6%. Physical exercise significantly reduced insulin response as an expression of increased insulin sensitivity and triglyceride levels.
A 2011 meta-analysis concluded that structured exercise training that consists of aerobic exercise, resistance training, or both combined is associated with HbA1c reduction in patients with type 2 diabetes.
Aerobic training and resistance training are both beneficial; however, a combination of the two is perhaps the optimal form of exercise for people with type 2 diabetes. Evidence also suggests that high-intensity exercise improves glycemic control more than low-intensity exercise.
Several meta-analyses have concluded that physical exercise has a positive effect on blood pressure in both normotensive and hypertensive cases.
A meta-analysis included randomized controlled trials lasting ≥4 weeks investigating the effects of exercise on blood pressure in healthy adults. The study included 93 trials, involving 105 endurance, 29 dynamic resistance, 14 combined, and 5 isometric resistance groups, totaling 5223 participants.
Systolic blood pressure was reduced after endurance (-3.5 mmHg), dynamic resistance (-1.8 mmHg), and isometric resistance (-10.9 mmHg). Reductions in diastolic blood pressure were observed after endurance (-2.5 mmHg), dynamic resistance (-3.2 mmHg, isometric resistance (-6.2 mmHg), and combined (-2.2 mmHg) training. BP reductions after endurance training were greater.
Chronic obstructive pulmonary disease
The positive impact of physical exercise on patients with COPD is well documented. A 2015 Cochrane Review/meta-analysis (McCarthy et al., 2015), included 65 RCTs involving 3822 participants.
The authors found statistically significant improvement for all included outcomes. In four important domains of quality of life (Chronic Respiratory Questionnaire (CRQ) scores for dyspnea, fatigue, emotional function). Both functional exercise and maximal exercise showed statistically significant improvement.
All patients with COPD, particularly the more severe cases, benefit from physical training. Initially, the physical training must be supervised, individually tailored, and include a combination of endurance training and strength training.
There is strong evidence that physical exercise, both aerobic and resistance training, has an effect on self-reported pain and general level of functioning in individuals with osteoarthritis in the knee and hip joints.
According to studies the effect of resistance training is comparable to oral non-steroidal anti-inflammatory drugs and acupuncture, and the effect of aerobic training on knee osteoarthritis is comparable to intra-articular corticosteroid injections.
A meta-analysis from 2015 (Fransen et al., 2015) evaluated the role of exercise in patients with knee osteoarthritis. In total, data from 44 trials (3537 participants) indicated that therapeutic exercise provides short-term benefits such as reduced pain, improved physical function, quality of life, and improved quality of life.
A meta-analysis from 2008 comprising 18 studies with 2832 patients with knee osteoarthritis 55–74 years of age found that self-reported measurements of pain, physical functioning, muscle strength, gait speed, and balance improved in 56–100% of the studies. There was also an improvement in strength in musculus quadriceps femoris.
One randomized controlled trial included 319 patients with rheumatoid arthritis (de Jong et al., 2003). The intervention group took part in twice-weekly training sessions lasting 75 min. Each session consisted of bike fitness training, strength training in the form of circuit training, and weight-bearing sport in the form of volleyball, football, basketball, or badminton.
The program lasted for 24 months, and the researchers found that intensive weight-bearing training programs increased functional status and physical wellbeing without having a negative effect on disease activity.
Several studies have shown that aerobic and resistance exercise programs do not change the number of inflamed joints, radiological joint damage, disease activity, or systemic inflammatory markers in patients with low to moderate RA disease activity.
As we can see there is a lot of evidence that suggests that exercise is just as effective as medical treatment, in some occasions is even more effective or adds to the effect of the medical treatment.
Not only does exercise is an excellent treatment option for multiple health conditions but is also a preventive measure. If performed at a young age, it can prevent, in a lot of cases, the development of them in the first place.
In the current medical world, it is traditional to base all therapies on “evidence-based medicine”, and prescribe the most effective treatment. Well, although not as easy as taking a pill, exercise is one of the best ways to prevent and treat multiple health chronic conditions and there’s evidence to prove it.
B. K. Pedersen, B. Saltin. Exercise as medicine – evidence for prescribing exercise as therapy in 26 different chronic diseases. 2015. Scand J Med Sci Sports. https://doi.org/10.1111/sms.12581