Top 3 Studies: Smartphones before bed, fasting and muscle, HIIT and cognition

Wondering what’s new in research? What hasn’t been widely publicized in the media, yet has practical use? This may help: here are three of the studies most often favorited by the readers of the September issue of [Examine Personalized](: 1) The smartphone blues At Examine.com, we may try to grab your attention on occasion. Sorry, but we do have to sell something in order to feed our growing team of researchers. (If only they’d work for free!) Yet Examine.com isn’t carefully crafted to be addictive, unlike social media feeds and 24-hour news sites that keep you up to date but also up too late. Few randomized trials have been done on the health effects of phone use, though. Luckily, an insightful one was recently published: [Bedtime phone use impairs sleep quality]() Background: Blue light promotes wakefulness, and smartphones produce blue light. It has therefore been suggested that reducing phone use before bedtime should improve [sleep quality]() and thereby mood and memory. The study: In a 4-week randomized controlled trial, 38 adults were assigned to two groups: restriction (no phone use 30 minutes before bedtime) or no restriction. Sleep habits, sleep quality, presleep arousal, and mood were measured. The results: Limiting smartphone use before bedtime was found to improve sleep quality, mood, and working memory. Note: It would have been interesting to include a group who used smartphones running a program filtering out blue light, to ascertain whether blue light was the main reason why smartphone use before bedtime impaired sleep quality. 2) Fasting gainz Fasting may seem like a hot new trend or even a fad, but it certainly isn’t. Humans have practiced regular fasting for ages, by necessity rather than choice. Three square meals a day is a relatively recent invention, and isn’t dietary law. However, fasting isn’t a panacea. Nothing is. Among the concerns it raised are its effect on muscle gain. The following study explored this issue. [Keep your muscle while fasting](=) Background: Intermittent fasting (IF) has become popular among the health conscious, but it could reduce lean body mass (LBM). Resistance training can slow or stop the loss of LBM even in the face of calorie restriction. How does pairing IF with resistance training affect LBM? The study: This systematic review selected 8 studies out of the 39 that met its criteria. It aimed to gauge the effects of IF combined with resistance training on body weight, fat mass, and LBM. It also aimed to assess adherence to the protocol. The results: In general, LBM was maintained when IF was combined with resistance training. Given adequate protein and calories, IF with resistance training can increase LBM and decrease fat mass. Only two of the included studies tracked adherence rates; those studies, which focused on time-restricted feeding (TRF, which involves a prolonged daily fasting period), found on average a nearly 96% adherence rate over the course of 8 weeks. Note: The included studies lasted only 4–8 weeks. Future studies will need to assess the long-term effects of IF combined with resistance training. Future studies will also need to assess IF practices other than the two this review focused on — TRF and Ramadan fasting (a religious practice that has Muslims refrain from food or drink from sunrise to sunset for one month of the Islamic calendar). 3) HIIT me with your best shot If someone asked for your preference between HIIT, MISS, and LISS, how would you respond? Would you think they’re reciting a nursery rhyme? There’s no need to memorize the dozens of exercise and nutrition acronyms floating around the Web, but HIIT is one to keep an eye on, as more and more studies show it has possibly unique benefits. For example… [High-intensity interval training benefits cognition at any age]() Background: Moderate-intensity aerobic exercise has cognitive benefits for the old and the young, but what about high-intensity interval training (HIIT)? The study: This systematic review included 23 studies on the acute and long-term effects of HIIT on cognition. Modalities included cycling, sprinting, and circuit training, and outcomes measured included inhibition (tuning out irrelevant stimuli), working memory, and cognitive flexibility. The results: HIIT can acutely improve inhibition in children and adults, and can chronically improve inhibition and working memory in children. The authors emphasize the need for proper “dosing”, for taking individual differences into account, and for further research in older people. Note: Children naturally exhibit patterns of physical activity resembling high-intensity interval training, so this type of “intervention” can be easily implemented during the school day through recess or physical education. Any game that involves short, intense bouts of activity, such as tag, could foster brain health in children. --- Did you enjoy these summaries of recent studies? If so, check out [Examine Personalized]( and try it free for a week! Remember that these are only three summaries from Examine Personalized — subscribers have access to 150+ recent studies each month, targeted to their specific health interests. Sincerely, Kamal Patel [About Examine.com]() | [Support Us]( | [Instagram](=) | [Facebook]() | [Twitter](=) [I want an email once a month](=) | [Unsubscribe]( | [Update your profile]( | PO Box 592, Station-P, Toronto, Ontario M5S 2T1