Iron Supplementation and Eccentric Exercise
Condition: Muscle Damage; Oxidative Stress
Study type: Interventional

Summary: 
      Iron supplementation is very common in athletes, probably due to its catalytic role on the
      oxygen transport and optimal function of oxidative enzymes and proteins during exercise.

      Iron is also characterized as a potent pro-oxidant, as it can lead to increased production of
      reactive oxygen and nitrogen species (RONS) that are involved in critical biological
      processes, such as gene expression, signal transduction and enzyme activity. In exercise, low
      levels of RONS are essential for optimal force production, whereas excessive production of
      RONS can cause contractile dysfunction, resulting in muscle weakness and fatigue. On the
      other hand, RONS are involved in signaling pathways and up-regulation of the expression of
      several genes, and therefore, RONS can provoke favorable effects such as training
      adaptations.

      The purpose of the present study is to investigate the effect of iron supplementation on
      redox status, muscle damage and muscle performance after an acute bout of a valid muscle
      damaging eccentric exercise model in adults and children.
    

Detailed description: 
      Eccentric muscle work is an essential part of human daily activities, such as walking, and in
      particular, when walking downhill or descending stairs. It is also a component of almost all
      of the athletic actions. The most notable and well-described effect of eccentric exercise is
      the muscle damage that peaks one to three days after exercise and is accompanied by several
      hematological, biochemical and physiological responses. Excessive production of reactive
      oxygen and nitrogen species (RONS) has been reported as a result of eccentric exercise. The
      typical approach so far, was to provide antioxidants to minimize oxidative stress, yet the
      effectiveness of such an approach is still under debate. Earlier studies reported positive
      effects of antioxidant supplementation on muscle performance, muscle damage and redox status,
      whereas more recently, well-received studies pointed towards the negative impact of
      antioxidant supplementation.

      Iron is an essential element for the completion of numerous important biological functions,
      and also for optimal exercise performance. It is a vital component for the formation of
      oxygen-transport and iron-storage proteins hemoglobin and myoglobin, and for the most
      favorable function of many oxidative enzymes that affect the intracellular metabolism.
      Therefore, iron supplementation is commonly used to avoid exercise-induced perturbations of
      iron homeostasis and maintain the required iron stores that are necessary to address exercise
      needs or enhance physical performance. Iron is also characterized as a potent pro-oxidant, as
      it can lead to increased production of reactive oxygen and nitrogen species (RONS) that are
      involved in critical biological processes, such as gene expression, signal transduction and
      enzyme activity. Nevertheless, the role of iron on modifying redox responses after eccentric
      exercise has not yet been examined.

      In a double blind, randomized cross over study that will be conducted in two cycles, healthy
      men and boys will receive either the iron supplement (37mg of elemental iron per day for
      three weeks before and one week after the eccentric exercise) or the placebo.

      Blood samples will be collected: a) in adults prior to, at the end of first supplementation
      period, 24, 48,72 and 96 hours following an acute bout of eccentric exercise (5 sets x 15 max
      reps), and b) in children prior to, at the end of first supplementation period and 72 hours
      following the same exercise protocol. Blood drawings will be repeated at the same time points
      during the second supplementation cycle.

      The aims of the present research are to investigate:

        -  The effect of an acute bout of eccentric exercise on muscle performance, redox status,
           and iron status.

        -  The effect of three weeks of iron supplementation on muscle performance, redox status,
           and iron status.

        -  The effect of four weeks of iron supplementation on muscle damage, muscle performance,
           and redox status after an acute eccentric exercise bout.

        -  The effect of age on muscle damage, muscle performance and redox status after an acute
           eccentric exercise bout and iron supplementation.
    

Intervention name(s): Iron supplement Resoferon Ferrous Sulfate; Placebo
Intervention type(s): Dietary Supplement; Dietary Supplement
Intervention description(s): Oral supplementation with one tablet of iron supplement [Resoferon Ferrous Sulfate 125 (37) mg]
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Double (Participant, Investigator)
Keywords: eccentric exercise; pro-oxidants; free radicals; adults; children