Stair walking trumped caffeine in psychoactivity
Psychologists from the University of Georgia have shown that walking up and down stairs can subjectively increase overall body tone to a greater extent than caffeine.
According to statistics, in the United States alone, about 38 percent of people experience chronic fatigue. The phenomenon affects not only the quality of life, but also the economy: reduced productivity associated with fatigue costs employers more than 100 billion dollars annually. One of the most common and affordable ways to artificially increase tone is to take psychoactive substances, particularly caffeine, which is found in tea, coffee and Coca-Cola (35-50 milligrams in a can). Past work has shown that even a minimally discernible dose of the substance (up to 12.5 milligrams) can increase energy, and 100-200 milligrams can increase motivation for cognitive tasks. An alternative source of “fast” energy is physical exercise. However, their effects have not been sufficiently studied.
To compare the tonic properties of caffeine and motor activity, American scientists conducted an experiment with 18 women aged 18-23 years with chronic sleep deprivation. At the first stage, they filled out a sociodemographic questionnaire, indicated the frequency of sports and the weekly amount of caffeine consumed. The subjects were then divided into three groups: the first went up and down stairs for 10 minutes; the second took a capsule with 50 milligrams of caffeine and rested for 30 minutes. The control group received a placebo capsule and did not exercise. Before and after the stimuli, the researchers studied the participants' mood, heart rate, as well as their pain sensations and motivation for cognitive tasks.
Before and after the stimulation, volunteers also performed two cognitive tests - The Continuous Performance Task (CPT) and the n-back task. Under the conditions of the former, they were randomly presented with 12 Latin letters for 200 milliseconds each. Participants had to respond to each presentation of the letter “X” provided that it was preceded by the letter “A”. The n-back task repeated the scenario of the previous test, but this time the interval between the letters of the target sequence (“A, A”) was two (2-back) or three steps (3-back), such as “A, C, A” and “A, E, C, A,” respectively. In this way, the scientists were able to assess the speed of attention and working memory of the subjects and compare the effects of different modes of stimulation - exercise and a psychoactive substance - on the scores.
Dynamics of vigor scores 30 (Post-1), 51 (Post-2) and 72 minutes (Post-3) after exercise (gray), caffeine (orange) and placebo (blue) / ©Derek D. Randolph et al, Physiology & Behavior, 2017
During the experiment, participants in the first group walked an average of 988.44 ± 114.53 steps at an easy pace with a heart rate of about 62.39 ± 12.74. Most of them felt no muscle pain and yet were subjectively more alert and energetic than the groups taking caffeine or placebo. The duration of the effect (about ten minutes in the stair-walking group) was independent of background conditions such as anger, degree of fatigue or depression. Meanwhile, a comparison of the results of cognitive tests revealed no significant differences between the volunteers: their reaction times, as well as the number of correct and incorrect answers before and after stimulation were almost identical. In addition, the visual scale of motivation to solve cognitive tasks did not reveal any significant difference.
According to the authors, despite the small sample size, the findings allow for a preliminary assessment of the effects of different ways of increasing tone on self-perception. In the experiment, a ten-minute walk up the stairs sharply increased the vigor of the subjects, whereas caffeine subjectively had no effect on them. However, motor activity did not alter motivation, attention span, and working memory, nor did it improve their experience of chronic fatigue. This is consistent with past work, which has shown that a single bout of physical activity is generally unable to eliminate “baseline” fatigue, but more easily corrects more mobile levels of overall energy. Nevertheless, such exercise may serve as an alternative to psychoactive substances for people with busy schedules, the researchers said.
Details of the study are presented in the journal Physiology & Behavior.
Earlier it became known that standing work reduces the risk of coronary heart disease, and walking increases creativity.