The cell -- Cellular life span -- Genes, genetic heterogeneity, and exercise phenotypes -- Proteins and exercise -- Extracellular matrix and exercise -- Regulation of intracellular ion composition and pH -- Inter- and intracellular signaling -- Energy turnover and substrate utilization -- Generation and disposal of reactive oxygen and nitrogen species -- Cellular responses to environmental stress -- Exercise and the cardiac myocyte -- Exercise and endothelium -- Activity-dependent adaptive responses of skeletal muscle fibers -- Exercise and the alveolar and bronchial epithelial cell -- Exercise and the liver cell -- Exercise and the adipocyte -- Erythrocytes -- Leukocytes -- Exercise and the brain.