While searching to see if video game playing may influence blood glucose levels, a paper that had been published by a group of Harvard researchers caught my attention. The title was "Blood sugar level follows perceived time rather than actual time in people with type 2 diabetes".

    These researchers believed that the mind may impact the body's physiological response, such as blood glucose level in a diabetic person. They wanted to see if manipulating people's thoughts about how long they had played the video game would change their blood glucose levels. That was interesting, wasn't it?

    They recruited 47 volunteers who had type 2 diabetes mellitus (≥ 12-month duration; 24 women; mean age = 54.1 years, standard deviation = 12.2 years), and they were being treated with diet and metformin, an antidiabetic medication. The study participants fasted for at least 8 hours before they came to the laboratory for the studies, beginning at 9:00 AM (mean fasting hours: 11 hours 47 minutes; standard deviation: 1 hour 34 minutes).

    When study participants arrived at the laboratory, they were told that the study goal was to understand the cognitive functioning of people with type 2 diabetes. They were randomly assigned to one of three experimental conditions: Fast, Normal, and Slow. They were asked to leave behind all devices that indicated time (e.g., phones, tablets, watches). Then they were taken to a separate laboratory room where they played three simple video games for 90 min and for approximately the same amount of time for each game.

    Participants in the Normal condition viewed a clock on the desk that indicated the actual time passing while they played video games; that is, their clocks correctly showed that 90 minutes had passed by the end of the task period. Participants in the Slow condition, however, viewed a clock rigged to run two times slower than the actual time so that it indicated only 45 minutes passed by the end of the task period. Participants in the Fast condition viewed a clock that ran two times faster than the actual time, so it indicated that 180 minutes had passed by the end of the task period.

    With the same duration of the 90 minutes of game playing, the study organizers made the participants believe that they had either played 45 minutes, 90 minutes, or 180 minutes in total. It is a mind game rather. Can you guess what the blood glucose levels are like for each group by the end of video game playing?

    The results showed that the glucose levels dropped by the end of the 90 minutes in all 3 groups: Participants who had been watching fast clocks (who thought that they had played for 180 minutes) showed a greater decrease in blood glucose level (Mean = 23.5 mg/dL) than those in the Normal group (who thought that they had played 90 minutes) (Mean = 15.1 mg/dL), and those with slow clocks (who thought that they had played 45 minutes) showed a lesser decrease in blood glucose level (mean = 9.8 mg/dL) than those in the Normal group. Across all participants, the magnitude of blood glucose level decrease was associated with the duration of perceived passed time (r = 0.53; P < 0.01).

    These study results were fascinating in a few ways: blood glucose levels changed according to how much time the study participants believed had passed instead of how much time had passed; another thing that impressed me was how much influence the psychological processes could directly exert on the body, an average ~15 mg/dL blood glucose level drop was a significant amount, with the belief of a longer duration of effort, the blood glucose drop was even more to ~23.5 mg/dL, about 50% more. This study did show that our minds could directly impact our body's response and have a role in our overall health.

    This study also provided an answer to my original curiosity: playing video games for 90 minutes could lower blood glucose by ~ 15 mg/dL in diabetic people, which sounded like a very effective method for blood glucose management. I wonder if any studies had been done on video game playing and blood glucose in healthy adults. Would the blood glucose level drop in healthy people as much as seen in diabetic people?

    If thoughts may alter our body's responses, what if giving people some magic pills that claim to "lower blood glucose" would have any real impact? This may have the so-called "placebo" effect seen in clinical studies and why researchers typically have a placebo control group in the study design. What if telling people that they had eaten doubled kcals than what they should have eaten, would their blood sugar go up or feel fuller or even gain weight? If we have the belief that something may happen, then something may actually happen. Some of us may have already experienced it in life. We need to keep our thoughts positive for good health.

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Reference:

Chanmo Park, Francesco Pagnini, Andrew Reece, Deborah Phillips, Ellen Langer. Blood sugar level follows perceived time rather than actual time in people with type 2 diabetes. Proc Natl Acad Sci. 2016. 19;113(29):8168-70. doi: 10.1073/pnas.1603444113.