Metallothioneins are low molecular weight, cysteine-rich, heavy-metal binding proteins. They are present in some Prokaryota, fungi, plants and animals. Attempts to isolate native plant proteins failed but many metallothionein genes were identified in mono- and dicotyledons and also in some gymno- sperms and algae. They are organised in small gene families, like in animals genomes and their expression is upregulated by different endo- and exogenous factors, including metal ions.

Intracellular protein destroying and impairment of their synthesis result in disturbance of cell homeostasis and can lead to cell death. Counteracting these changes the cell induces synthesis of stress proteins among others. Physical exercise has stress attributes, especially if it is a long-lasting and intensive one. It can be assumed that this will bring about an intensification of stress protein expression what was experimentally confirmed. However the significance of this reaction is not fully clear taking into account the variety of functions the stress protein act in the organism.

All organisms are exposed to reactive oxygen species such as hydrogen peroxide (H2O2), superoxide anion (O2· –) and hydroxyl radical (·OH) as unavoidable products of oxidative metabolism. Many biotic and abiotic factors such as: pathogens, air pollutants, salts, xenobiotic, heavy metals, UV radiation initiate ROS formation. The main sites of ROS formation in plant cells are chloroplasts, peroxisomes and mitochondria. ROS can cause wide-ranging damage to many macromolecules including proteins, lipids and nucleic acids, eventually leading to cell death.

Increasing rate of aged people in societies of developed countries is inevitably connected with occurrence of health problems closely related to this period of life. Ageing as well as old age itself, being a stage of life, are associated with coexisting involutional changes in organs, systems of organs, and old age diseases, accompanying this period of life. In physiological ageing process the disorders mainly concern haematopoesis, especially in conditions of so called hematological stress.

Lipid metabolism plays a pivotal role in membrane biogenesis, synthesis of lipid second messengers and membrane repair processes. Recently, disturbances in a balance between synthesis and degradation of lipids have been ascribed to participate at early stages of cancer development.