Think your dog likes food? Try praising her. Then try praising her for not liking food as much as she likes praise. Researchers at Emory University recently set out to determine which dogs like more: food or praise. An Emory news release reports that the researchers first trained the dogs to associate three different objects with different outcomes. A pink toy truck signaled a food reward; a blue toy knight signaled verbal praise from the owner; and a hairbrush signaled no reward, to serve as a control. The dogs were then tested on the three objects while in an fMRI machine that revealed activity in their brains’ reward center. Ready? The envelope please….All of the dogs showed a stronger response for the reward stimuli compared to the stimulus that signaled no reward. No, not surprising. Four of the dogs showed a particularly strong activation for the stimulus that signaled praise from their owners. Nine of the dogs showed similar neural activation for both the praise stimulus and the food stimulus. And two of the dogs consistently showed more activation when shown the stimulus for food. Wait, there’s more. In the next experiment, each dog was familiarized with a room that contained a simple Y-shaped maze constructed from baby gates: One path of the maze led to a bowl of food and the other path to the dog’s owner. The owners sat with their backs toward their dogs. The dog was then repeatedly released into the room and allowed to choose one of the paths. If they came to the owner, the owner praised them. Most of the dogs alternated between food and owner, but the dogs with the strongest neural response to praise chose to go to their owners 80 to 90 percent of the time.
Taking this job and shoving it may be good for your health–if you really hate the job to begin with. Researchers at Ohio State University are convinced that job satisfaction in your late 20s and 30s has a real influence on overall health in your early 40s. How do they know? An Ohio State U news release reports that the researchers examined job satisfaction trajectories for people from age 25 to 39, then asked the participants about a variety of health measures after they turned 40. The researchers put participants in four groups: consistently low and consistently high job satisfaction, those whose satisfaction started high but was trending down and those who started low but were trending higher. Here’s what they found: 45 percent of participants had consistently low job satisfaction; 23 percent had levels that were trending downward through their early career; 15 percent were consistently happy at their jobs; and about 17 percent were trending upward. Unsurprisingly, the researchers found that mental health, rather than physical health, was most affected by people’s feelings about their jobs. Those in the low job satisfaction group throughout their early careers scored worse on all five of the mental health measures, with higher levels of depression, sleep problems and excessive worry. Those whose job satisfaction started out higher but declined through their early career were more likely than those with consistently high satisfaction to have frequent trouble sleeping and excessive worry, and had lower scores for overall mental health. And those whose scores went up through the early career years did not see any comparative health problems. Wait, there’s more: those who were in the low satisfaction group and those who were trending downwards reported poorer overall health and more problems like back pain and frequent colds compared to the high satisfaction group.
Fidgeting feet may be the key to healthy legs, if researchers at the University of Missouri have got things right. A U of Missouri news release reports that researchers at the medical school compared the leg vascular function of 11 healthy young men and women before and after three hours of sitting. While sitting, the participants were asked to fidget one leg intermittently, tapping one foot for one minute and then resting it for four minutes, while the other leg remained still throughout. On average, the participants moved their feet 250 times per minute. The researchers then measured the blood flow of the popliteal — an artery in the lower leg — and found that the fidgeting leg had a significant increase in blood flow, as expected, while the stationary leg experienced a reduction in blood flow. Other research has shown that increased blood flow and its associated shear stress — the friction of the flowing blood on the artery wall — is an important stimulus for vascular health.
Enjoy the summer Olympics, because by 2085 the earth’s climate will be so hot that very few cities will be able to host them. That’s the verdict from researchers at the University of California in Berkeley, who examined the viability of future Olympics sites based on a measurement that combines temperature, humidity, heat radiation, and wind—their wetbulb globe temperature (WBGT). A UC Berkeley news release reports that the researchers focused on cities in the Northern Hemisphere, home to 90 percent of the world’s population, and they considered only cities with at least 600,000 residents, the size considered necessary for hosting the games. Cities with elevations over a mile above sea level were omitted, as the most recent Olympic games hosted at such an altitude (Mexico City in 1968) faced challenges of their own. The findings suggest that by 2085, Istanbul, Madrid, Rome, Paris, and Budapest—all cities that are or were in contention for either the 2020 or 2024 Summer Olympics—would be unfit to host the games. Tokyo, the city that has secured the 2020 summer Olympiad, would also be too hot to ensure athlete safety. Among the 8 out of 543 cities outside of western Europe would qualify as “low-risk” sites, including St. Petersburg, Russia; Riga, Latvia; Bishkek, Kyrgyzstan; and Ulaanbaatar, Mongolia. In North America, Calgary, and Vancouver would join San Francisco as the only three suitable sites. Latin America and Africa combined would fail to provide a single viable city. Western Europe is home to 25 cities that would be “low-risk” sites in 2085, according to the calculations. But by the 22nd century, if their projections play out, the scientists concluded only four Northern Hemisphere cities would be left on the list: Belfast and Dublin, Ireland; and Edinburgh and Glasgow in Scotland.
In most American cities, commuting by bike is faster and cheaper than driving to work. Now comes another reason to think about pedaling instead of stepping on the gas pedal: people who ride bikes weigh less than people who drive. The Imperial College of London reports that researchers at the school monitored 11,000 volunteers in seven European cities, asking them how they move around the city, which mode of transport they use and how much time they spend traveling. They also asked the volunteers to record their height and weight, and to provide information about their attitudes towards walking and bicycling. The take away: people who drive cars as their main form of transport are on average four kilograms (8.8 lbs) heavier than those who ride bikes.
Which is more likely to lead to regrettable sex, alcohol or pot? That’s what researchers at New York University wanted to know, so they interviewed 24 adults (12 males and 12 females) who recently used marijuana before sex. An NYU news release reports that the researchers found that, compared to marijuana, alcohol was more commonly associated with social outgoingness and use often facilitated connections with potential sexual partners; however, alcohol was more likely than marijuana to lead to atypical partner choice or post-sex regret. They also found that while some people reported that marijuana made them more selective in choosing a partner, many participants— both male and female—felt that their “standards” for choosing a partner were lowered while under the influence of alcohol. Wait, there’s more: While people often described favorable sexual effects of each drug, both alcohol and marijuana were associated with a variety of negative sexual effects including the very negative effect of sexual dysfunction. For example, marijuana use was linked to vaginal dryness and alcohol was commonly described as increasing the likelihood of impotence among males. Both drugs appear to be potentially associated with increased feelings of self-attractiveness, but possibly more so for alcohol, and participants reported feelings of increased sociability and boldness while consuming alcohol.
Contrary to some opinions, and to the findings of a well-known 2014 study published in the journal Science suggesting that running made mice forget things, a new study has found that there is no connection between running and the loss of memories. A news release from researchers at Texas A&M reports that researchers at the school did basically the same experiment as the 2014 study, but they used rats instead of mice, because rats are more like humans physiologically. This time, the researchers found that rats who ran further had much greater neurogenesis in their hippocampus (growth of new neurons in the part of the brain that holds memories), and all rats who had access to a wheel (and therefore ran at least some), had greater neurogenesis than the sedentary group. On an average, they ran about 48 miles in four weeks, and neuron formation doubled in the hippocampus of these animals. They also found that despite differing levels of increased neurogenesis, both moderate runners and brisk runners (those who ran further than average) showed the same ability as the sedentary runners to recall the task they learned before they began to exercise. This means even a large amount of running (akin to people who perform significant amount of exercise on a daily basis) doesn’t interfere with the recall of memory.
Everyone knows why women fake orgasms; now researchers at Yale have come up with a theory about why women have orgasms in the first place. A Yale news release reports that, because orgasms play no obvious role in human reproduction, the research focused on a specific physiological trait that accompanies human female orgasm — the neuro-endocrine discharge of prolactin and oxytocin. When the scientists looked for this in other mammals they found that in many mammals this reflex does play a role in ovulation. So, they theorize, female orgasm may have evolved as an adaptation for a direct reproductive role — the reflex that long ago induced ovulation. They note that “This reflex became superfluous for reproduction later in evolution, freeing female orgasm for secondary roles,” like pleasure for instance. Wait, there’s more: a comparative study of female genitalia revealed that, coincidental with the evolution of spontaneous ovulation, the clitoris was relocated from its ancestral position inside the copulatory canal. This modification made it less likely that the clitoris receives adequate stimulation during intercourse to lead to the neuro-endocrine reflex known in humans as orgasm. The researchers note that “Such evolutionary changes are known to produce new functions, as is well established for feathers, hair, or swim bladders, etc., which originated for one purpose and were coopted into secondary functions later.” So, sure, orgasms are like feathers. But not exactly.
You know that wonderful high that often follows a good workout? Many post-menopausal women don’t know it, and researchers at the University of Missouri now think they know why. A U of Missouri news release reports that the researchers believe they found a connection between lack of ovarian hormones and changes in the brain’s pleasure center, a hotspot in the brain that processes and reinforces messages related to reward, pleasure, activity and motivation for physical exercise. The researchers compared the physical activity of rats that were highly fit to rats that were less fit, studying rats’ use of running wheels set up in the cages before and after the rats had their ovaries removed. They also examined gene expression changes of dopamine receptors within the brain’s pleasure center. Here’s what they found: The high-fit rat group had more activity in the brain’s pleasure center, which correlated with greater wheel running before and after the loss of ovarian hormones. But…. the high-fit rats still saw a significant reduction in wheel running after their ovaries were removed, and that reduction in running correlated with a reduction in their dopamine signaling levels, indicating that the brain’s pleasure center could be involved.
Yes, sitting all day is bad for you. And yes, exercise is good for you. So how much exercise to you need to erase the damage of a day of sitting? That’s the question researchers at the Norwegian School of Sport Science set out to answer. HealthDay reports that the researchers reviewed 16 previously published studies that included more than one million people, dividing the participants into four groups: those who got about 5 minutes of moderate-intensity exercise a day; 25 to 35 minutes a day; 50 to 65 minutes day; and 60 to 75 minutes a day. Here’s what they found: an increased risk of early death ranged from 12 percent to 59 percent, depending on how much exercise the participants got. They also found that people in the most active group, those who got 60 to 75 minutes per day, had no increased risk of mortality, even if they sat for more than eight hours a day. They put the answer to the question “how long do you have to exercise to erase the damage of a day of sitting?” at “one hour, thanks”. The good news? The exercise can be something as easy as brisk walking.