1 23 European Journal of Applied Physiology ISSN 1439-6319 Eur J Appl Physiol DOI 10.1007/s00421-015-3185-x Temporal dynamics of the circadian heart rate following low and high volume exercise training in sedentary male subjects Herbert F. Jelinek, C. Karmakar, A. M. Kiviniemi, A. J. Hautala, M. P. Tulppo, T. H. Mäkikallio, H. V. Huikuri, A. H. Khandoker, et al.