The Positive Physiological Effects of Sports Activity on the Living Organism

Introduction

Over the past few decades we have observed a substantial increase in the numbers of overweight and obese individuals in the Triad Countries, this is not limited to the human population but also affects the pets. To combat this condition that can lead to many health issues, the states promote physical activity and sports. These can participate in preventing or even reversing these conditions, with overall positive effect on health and longevity. Physical activity can be defined as any voluntary movement which leads to the uptake of energy, it can be anything from cleaning the house to working out. We are going to focus our attention on sports which is a subsection of physical activity. Sports are very different from one living organism to another, but as a general definition we can consider it as a high energy demanding activity that is practiced with the goal of improving physical condition and in many cases personal and team performances. This activity is normally practiced on a regular basis, the frequency however depends on the species practicing, the sport and the physical condition of the individual. When it comes to our pets, we have influenced their physical conditions by altering the environment they live in. By doing so we changed their natural behaviour for example horses which normally travel about 10-20km a day are kept in boxes and are worked in a more intensive way for just one hour a day. In the case of dogs who are kept in apartments without having the space to freely run at any given time but depend on their owner to give him access to larger spaces. With all of this in mind, we are going to present the physiological benefits of regular sports activity on the organism but also emphasise the problems that can occur if this is overdone.

In this essay we would therefore like to further elaborate on the physiological effects of regular physical activity on the following organ systems; musculoskeletal system, nervous system, endocrine system, gastrointestinal and excretory system, immune system, cardiovascular system, respiratory system, respiratory system and the reproductive system.

In our conclusion we will give a brief summary of what are the main benefits of regular physical activity and what are the dangers associated with over-exercising. Furthermore, we would like to expand on possible methods to make our pets more active.

Skeletal Muscle

The major function of skeletal muscle is to produce motion and aid in the maintenance of posture. In order to achieve this, it must be able to efficiently adapt to the ever-changing demands exerted on it. The living organism is able to promote the latter trough training. Training can be characterised into two basic types i.e. aerobic or endurance training, which is a type of exercise that affects mainly depends primarily on the aerobic energy-generating processes in the muscle and anaerobic or resistance training, which is the type of exercise that depends primarily on the anaerobic energy-generating process in the muscle (e.g. glycolysis) (Manley, 1996).

The primary response to resistance training includes the buildup of muscle strength. On a cellular level the latter is primarily mediated by increases in the synthesis of protein filaments that constitute the actin and myosin filaments. As it has been demonstrated in human and animal studies this in turn is mediated by increased production of myogenic mRNAs, increased production of ribosomal RNA and proteins, activation of initiation factors, as well as adequate availability of appropriate amino acids (Adams, 2010; Bickel et al., 2005; Haddad and Adams, 2002).

Furthermore, it is becoming increasingly widely accepted that above mentioned processes of muscle hypertrophy (i.e. increase in muscle size), are also supported by the incorporation of new myonuclei into myofibers. The former are derived from satellite cells (i.e. the muscle stem cells responsible for longitudinal and cross-sectional postnatal growth), through a complex process of differentiation (Adams, 2010; Dayanidhi and Lieber, 2014; Petrella et al., 2008).

Adaptations of muscle to resistance training also include increased size and complexity of the neuromuscular junction as well as more efficient recruitment of the muscle fibres, which further contribute to better motor performance (Birch et al., 2004; Deschenes et al., 2000; Duchateau et al., 2006). Lastly increased strength of the connective tissue in tendons, and ligaments can be observed in connection to this type of exercise (Manley, 1996; Brumitt and Cuddeford, 2015).

In endurance trained muscle an increase in size and number of mitochondria, increased capillarization of muscle, increased glycogen storage capacity as well as an increased activity of oxidative enzymes and myoglobin content, can be observed. These changes provide muscle with a better energy supply which in turn supports better performance at considerably higher rates of work . The currently accepted model suggests that on a cellular level, alterations in expression levels of diffusible gene copies (i.e. mRNAs) are responsible for modulating the above-mentioned changes (Manley, 1996; Flück, 2006).

Besides increasing athletic performance, exercise appears to be a valuable tool for disease treatment and prevention. For instance resistance exercise can help prevent and reverse muscle atrophy, that is a decrease in muscle size, which can result from aging long-term bed rest or prolonged immobilization of body parts following injury (Little and Phillips, 2009). On the other hand however, excessive demands on the muscle may result in mechanical damage to the muscle itself and this in turn may also promote mechanical damage to bones and joints, therefore training should always be progressed with caution.