Vitamin D as a Factor Modifying Adaptation to Exercise
Condition: Vitamin D3 Deficiency
Study type: Interventional

Summary: 
      Physical activity is a recommended, indispensable element of a healthy lifestyle as well as a
      countermeasure against many diseases often accompanied by the acute or chronic low grade
      inflammation. Papers published in recent years have demonstrated the anti-inflammatory effect
      of exercise. Based on current knowledge of the topic, own experience and preliminary work, it
      is expected the proposed research to provide information on the mechanism either determining
      or limiting pro-healthy effects of exercise in different age groups of people. Three
      different training programmes will be investigated. Specific goals of the project include the
      following:

        1. Establish, whether regular Nordic Walking training and HIIT can reduce the low-grade
           systemic inflammation and which type of training is the most effective at doing so.

        2. Establish, whether regular training can prevent muscle sarcopenia and assess if those
           changes are related to the concentration of the autophagy-inducing stress protein,
           HMGB1.

        3. Establish, whether regular Nordic Walking training alters iron metabolism and evaluate
           its correlation with the inflammatory markers and bone-morphogenesis.

        4. Establish, whether muscle-released irisin signals growth in the BDNF concentration in
           response to exercise and if these changes improve cognitive function.

        5. Establish, whether Nordic Walking or HIIT training effectively improve the blood lipid
           profile and aerobic capacity, and if these effects correlate with the blood 25-OHD
           concentration.

        6. Establish, whether concentration of vitamin D alters adaptation to training and modifies
           immunological response to regular training process.
    

Detailed description: 
      The mechanism behind the anti-inflammatory effect of exercise is not fully understood. In
      some cases physical activity has proven almost/completely ineffective in reducing systemic
      inflammation. Thus, evaluating factors, which modify this response, is of particular
      significance. One of them may be related to iron metabolism. It is has been suggested that
      regular training reduces body iron stores, which can contribute to the anti-inflammatory
      response. Consequently, one of the anti-inflammatory effects of exercise can be related to
      changes in iron metabolism. Nevertheless, our preliminary data demonstrated that eight months
      of Nordic Walking training did not reduce body iron stores in approx. 25% of subjects, even
      if some of them were characterized by high blood ferritin (good indicator of body iron
      stores). This may be related to the effect of exercise on the concentration of hepcidin (main
      regulator of iron absorption, which acts as a negative regulator of iron efflux). It is well
      documented that a single bout of exercise induces an increase in blood hepcidin; however,
      data on the effect of regular training on the hepcidin concentration are limited.

      Vitamin D is another factor, which could influence the anti-inflammatory effect of exercise.
      It has been suggested that individuals involved in physical activity have higher
      concentrations of 25OHD (indicator of vitamin D status). Vitamin D inhibits the expression of
      pro-inflammatory cytokines, which is considered the main mechanism of its anti-inflammatory
      action. It is worth noting that population in Poland is characterized by low status of
      vitamin D. Thus, it is possible that the anti-inflammatory effect of exercise will be
      modified by the vitamin status. Moreover, vitamin D has been shown to protect against muscle
      atrophy both in elderly and younger people. Its concentration has been correlated with muscle
      strength.

      Inflammation has been observed to be associated with an increase of the autophagy-inducing
      stress protein, HMGB1, which mediates muscle atrophy. Measurement of plasma amino acid
      profile will be helpful to assess the impact of exercise on muscle proteolysis. Moreover, the
      link between exercise, vitamin D status and HMGB1 has not yet been established. In addition,
      a range of interactions induced by exercise involves the release of the newly discovered
      protein, irisin, form the muscle and its improving effect on the cognitive function through
      the synthesis of brain-derived neurotrophic factor (BDNF). Data on the effect of regular
      training on irisin concentration in elderly people is lacking.

      Overall, our research interest focuses on the role of the factors mediating the
      anti-inflammatory effect of exercise and the way they stimulate or inhibit adaptive changes.
      The proposed project draws on our long experience in investigating the effects of exercise on
      iron metabolism as well as other physical methods supporting the anti-inflammatory action of
      physical activity. Latest published papers indicate that the concentration of vitamin D, also
      in training adaptation, can modulate immunological response to exercise. Therefore, verifying
      our hypothesis would also allow us to determine if the concentration of vitamin D can limit
      adaptation to physical activity.
    

Intervention name(s): NW training; Placebo; HICT
Intervention type(s): Dietary Supplement; Dietary Supplement; Dietary Supplement
Intervention description(s): NW training; training with placebo; Training and vitamin D
Other intervention name(s): Training; vitamin D; Control group; resistance training
Intervention MeSH terms: Vitamin D
Allocation: Randomized
Intervention model: Sequential Assignment
Intervention model description: Model I
Women and men over 65 years old will participate in the training programme. All subjects will undergo a medical check-up before being subject to exercise. All procedures will be performed with the approval from the Bioethical Committee of the Regional Medical Society in Gdansk. One week prior to the beginning of the experiment, a battery of physiological and psychological tests will be performed. The same procedure will be repeated after the training period.
In addtition to training, supplementation of vitamin D (800IU and 4000IU) will be administered.
Model II
Young women will participate in the training programme. They will perform a high-intensity circuit training according to the ACSM. They will perform a single session of HICT and 12 units of HICT regularly. One week prior to the beginning of the experiment, a battery of physiological and psychological test will be performed. The same procedure will be repeated after the training period.
Masking: Single (Investigator)
Primary purpose: Prevention
Keywords: vitamin D; exercise; training; aging