Caffeine is the most widely consumed psychoactive substance worldwide, affecting numerous tissues and organs, with notable impacts on the central nervous system, heart, and blood vessels. The effect of caffeine on vascular smooth muscle cells is an initial transient contraction followed by significant vasodilatation. In this study we investigate the use of diffuse reflectance spectroscopy (DRS) for monitoring of vascular changes in human skin induced by caffeine consumption. DRS spectra were recorded on volar sides of the forearms of eight healthy volunteers at time intervals of 0, 30, 60, 120, and 180 min after consumption of caffeine, while one subject served as a negative control. Analytical diffusion approximation solutions for diffuse reflectance from three-layer structures were used to assess skin composition (e.g. dermal blood volume fraction and oxygen saturation) by fitting these solutions to experimental data. The results demonstrate that cutaneous vasodynamics induced by caffeine consumption can be monitored by DRS, while changes in the control subject not consuming caffeine were insignificant.

Faculty of Mathematics and Physics University of Ljubljana Ljubljana Republic of Slovenia

Physiol Res. 2025 Mar 24;74(1):161. doi: 10.33549/physiolres.930000.74.161. PubMed

See more in PubMed

Echeverri D, Montes FR, Cabrera MG, Prieto A. Caffeine’s Vascular Mechanisms of Action. Int J Vasc Med. 2010;2010:834060. doi: 10.1155/2010/834060. PubMed DOI PMC

Spott T, Svaasand LO. Collimated light sources in the diffusion approximation. Appl Optics. 2000;39:6453–6465. doi: 10.1364/AO.39.006453. PubMed DOI

Jacques SL. Optical properties of biological tissues: a review. Phys Med Biol. 2013;58:R37–R61. doi: 10.1088/0031-9155/58/11/R37. PubMed DOI

Lamola AA, Bhutani VK, Wong RJ, Stevenson DK, McDonagh AF. The effect of hematocrit on the efficacy of phototherapy for neonatal jaundice. Pediatr Res. 2013;74:54–60. doi: 10.1038/pr.2013.67. PubMed DOI

Friebel M, Roggan A, Muller G, Meinke M. Determination of optical properties of human blood in the spectral range 250 to 1100 nm using Monte Carlo simulations with hematocrit-dependent effective scattering phase function. JBO. 2006;11:34021. doi: 10.1117/1.2203659. PubMed DOI

Rajaram N, Gopal A, Zhang XJ, Tunnell JW. Experimental Validation of the Effects of Microvasculature Pigment Packaging on In Vivo Diffuse Reflectance Spectroscopy. Laser Surg Med. 2010;42:680–688. doi: 10.1002/lsm.20933. PubMed DOI PMC

Milanic M, Jia WC, Nelson JS, Majaron B. Numerical Optimization of Sequential Cryogen Spray Cooling and Laser Irradiation for Improved Therapy of Port Wine Stain. Laser Surg Med. 2011;43:164–175. doi: 10.1002/lsm.21040. PubMed DOI PMC

Bashkatov AN, Genina EA, Tuchin VV. Optical Properties of Skin, Subcutaneous, and Muscle Tissues: A Review. J Innov Opt Heal Sci. 2011;4:9–38. doi: 10.1142/S1793545811001319. DOI

Nachabe R, Hendriks BHW, van der Voort M, Desjardins AE, Sterenborg HJCM. Estimation of biological chromophores using diffuse optical spectroscopy: benefit of extending the UV-VIS wavelength range to include 1000 to 1600 nm. Biomed Opt Express. 2010;1:1432–1442. doi: 10.1364/BOE.1.001432. PubMed DOI PMC

Bydlon TM, Nachabe R, Ramanujam N, Sterenborg HJCM, Hendriks BHW. Chromophore based analyses of steady-state diffuse reflectance spectroscopy: current status and perspectives for clinical adoption. J Biophotonics. 2015;8:9–24. doi: 10.1002/jbio.201300198. PubMed DOI

Naglic P, Vidovic L, Milanic M, Randeberg LL, Majaron B. Combining the diffusion approximation and Monte Carlo modeling in analysis of diffuse reflectance spectra from human skin. Photonic Therap Diag X. 2014;8926:89260U. doi: 10.1117/12.2035747. DOI

Bjorgan A, Milanic M, Randeberg LL. Estimation of skin optical parameters for real-time hyperspectral imaging applications. J Biomed Opt. 2014;19:066003. doi: 10.1117/1.JBO.19.6.066003. PubMed DOI

Verdel N, Marin A, Vidovic L, Milanic M, Majaron B. Analysis of hemodynamics in human skin using photothermal radiometry and diffuse reflectance spectroscopy. SPIE Proc. 2017;10413:104130O. doi: 10.1117/12.2286043. DOI

Yang A, Palmer AA, de Wit H. Genetics of caffeine consumption and responses to caffeine. Psychopharmacology (Berl) 2010;211:245–257. doi: 10.1007/s00213-010-1900-1. PubMed DOI PMC

Kmetova K, Maronek M, Borbelyova V, Hodosy J, Celec P. Acute effect of cola and caffeine on locomotor activity in drosophila and rat. Physiol Res. 2021;70:287–292. doi: 10.33549/physiolres.934629. PubMed DOI PMC

Broz P, Rajdl D, Racek J, Trefil L, Stehlik P. Effect of Beer Consumption on Methylation and Redox Metabolism. Physiol Res. 2022;71:573–582. doi: 10.33549/physiolres.934863. PubMed DOI PMC

Sirotkin AV, Kolesarova A. The anti-obesity and health-promoting effects of tea and coffee. Physiol Res. 2021;70:161–168. doi: 10.33549/physiolres.934674. PubMed DOI PMC

Zhao Y, Yang G, Niu S, Zhang M, Gao F, Liu K. Evaluation of tissue perfusion status in moderate to late preterm. Physiol Res. 2022;71:607–614. doi: 10.33549/physiolres.934888. PubMed DOI PMC