The human body encounters a lot of strain in space as a result of physiological changes, adverse environmental condition and confinement in limited space over a long period of time. Due to the micro-gravity space environment, the body experiences a fluid shift as it is no longer under the influence of gravitational force. This also affects bone composition since the weightless body secretes excess phosphorus and calcium in urine. In addition muscles weaken since they are no longer subjected to exercise. Those involved in space flights use exercises, hormonal supplements as well as vitamin and mineral supplements to regulate bone and muscle loss.
Astronauts try to limit the weaknesses found in the muscles by doing weight load exercises that accelerate the earth's gravity. In spite of this, the flight crew still loses muscle strength and structure after long flights in space. Space flight alters the metabolism of the muscles as well as the process of muscle protein biosynthesis. Currently, the crew members use various exercise systems to maintain body and muscle mass. Such regulation methods include the use of a treadmill, an instrument for measuring the muscle power and an electrically resistant device. They are important exercises especially when incorporated with new systems and training programs. The exercises become more successful when a component for balance training is made to increase the flexibility in a gravitational environment. Besides, for an exercise system to be more successful it must incorporate cardiovascular training, resistance training as well as balance training so as to enhance artificial gravitational loading.
Compared with other human thermo regulation methods, exercises aid in maintaining the health of the space travelers since there is no use of supplements that might have negative effects in the body. Additionally, it is widely used to keep the muscles and the bones in good shape. Weightlifting form of exercises is very essential in maintaining the body shape. The treadmill is normally used for cardiovascular as well as in resistance exercises, and it is used together with rubber Bungies and harnesses for support and to prevent them from floating away. Exercise bicycles and resistive exercise devices are also essential in keeping the bones and muscles in good shape.
One of the disadvantages for intense exercises in muscle and bone retention is that they do not stabilize changes that occur in the muscle metabolism. Changes in metabolism during space flight result to muscle damage. Besides, use of exercises during the space travel reduces the productivity of the crew since it is very expensive to get a crew in the space and at the same time keep it healthy through exercises.
Dietary interventions such as nutritional supplements are essential and highly convenient in maintaining muscle and bone loss. Calcium and vitamin D supplements are one of the nutritional supplements widely used. In addition to that, vitamin K is used by many crew members and its main advantage is that it results to the increase in osteocalcin as well as alkaline phosphatase that increase the formation of new bones. The use of vitamin K supplement has proven very successful and it is widely used by flight members. Amino acid supplements are also used to balance protein biosynthesis in an attempt to reduce muscle loss.
Hormonal supplements also aid in reducing bone and muscle loss in space. They include products such as bisphosphonates and current antibody therapies. They are successful in preventing the bones from being reabsorbed due to the exposure of the bones to radiation in the course of space travel. In essence they limit bone turn over. The main disadvantage of using the biphosphonates is that it causes slow healing of fractures. However they are still widely used since the benefits outweigh the problem.
Intermittent hormonal supplements are anabolic that are used together with antibody therapies such as anti-sclerostin; they have been successful in increasing the formation of bones. Importantly, they promote the healing of fractures unlike the bisphosphonates. Moreover, use of siRNA mineral supplement offers remarkable results in reducing harmful effects of space travel to the skeleton. The disadvantage of using this supplement is that it is never understood how the bone tissue cells as well as the cells that make new bones react with the mechanical environment.
Mineral supplements are very essential during space flight because bone mineral loss is usually experienced even after the space travelers participate in cardiovascular and resistance exercise programs. Therefore, to get remarkable results both the mineral supplement and the exercise programs must be incorporated since all of them are necessary.
Other protein supplements effective in regulating the activities of the bone cells include dentin matrix protein 1 and matrix extracellular phosphor glycoprotein. The disadvantage of using the supplements is that more research has not yet been done to elucidate their metabolic mechanisms as well as their physiological effects. A protein supplement, sclerostin has been used successfully in preventing bone diseases. However there is need to understand its effects on clinical and molecular mechanisms so that it can be used by space travelers without fear. It therefore has a similar disadvantage with the dentrix matrix protein 1 and matrix extracellular phospho glycoprotein.
Basically, muscle protein breakdown in space is greater than protein biosynthesis. This is due to inactivity that occurs in the microgravity environment. Energy intake in space is depressed leading to the increase in catabolic hormones as well as in suboptimal nutrition. Therefore, the hormonal, vitamins and mineral supplements are very necessary.
According to one doctor in Galveston, "one cause of muscle atrophy in space is lack of muscular activity. That's why bed rest is a good model because it minimizes activity, and like astronauts, you lose muscle mass primarily in the legs." The doctor is known as Ferrado and also a professor in surgery. He continues to say that "when muscles are inactive, as they are in space, they do not make new proteins. If muscle breakdown rates are the same that means you lose muscle."
Amino acids, raw materials for proteins, have been very successful in increasing the protein synthesis for the space travelers. Unlike the other supplements, they are usually provided many times in a day and the results show that they are fully effective in maintaining body mass and protein synthesis rates.
In conclusion exercises and various supplements are essential in space flight. Most of the supplements have been successfully used although some of them have got side effects that may be harmful to the body. Use of exercises has been seen to more effective since the body does not suffer adverse effects following consumption of supplements. Deep research requires to be done on the supplements so that those involved in space flight can clearly understand the advantages as well as disadvantages of each supplement. Human neural muscular and musculoskeletal systems are usually affected by limited gravitational loading and exposure to radiation. That is why countermeasures are applied to enhance bone mass as well as muscle strength.