We know that spending lots of time sitting down isn't good for us, but just how much exercise is needed to match the negative health effects of sitting down all day? Research suggests about 30-40 minutes per day of building up a sweat should do it.

Up to 40 minutes of"moderate（温和的） to vigorous（有力的） intensity physical activity"every day is about the right amount to balance out 10 hours of sitting still, the research says—although any amount of exercise or even just standing up helps to some extent.

That's based on a study published in 2020 analyzing nine previous studies, involving a total of 44,370 people in four different countries who were wearing some form of fitness tracker. The analysis found the risk of death among those with a more sedentary（久坐的）lifestyle went up as time spent engaging in moderate-to-vigorous intensity physical activity went down. In other words, putting in some reasonably intensive activities—cycling, brisk walking, gardening--can lower your risk of an earlier death.

While analyses like this one always require some detailed dot-joining across separate studies with different volunteers, timescales and conditions, the benefit of this particular piece of research is that it relied on relatively objective data from wearables—not data self-reported by the participants.

The research based on fitness trackers is broadly in line with the 2020 WHO guidelines, which recommend 150-300 mins of moderate intensity or 75-150 mins of vigorous intensity physical activity every week to balance out sedentary behaviour.

Walking up the stairs instead of taking the lift, playing with children and pets, taking part in yoga or dancing, doing household chores, walking, and cycling are all put forward as ways in which people can be more active—and if you can't manage the 30—40 minutes right away, the researchers say, start off small.

"Going wireless is the future for just about everything!" That is a quote from scientist Sreekanth Chalasani, and we can't help but agree. Realizing this, a team of scientists has made a breakthrough toward wirelessly controlling human cells using sound, in a technique called "sonogenetics (声遗传学)." This concept may seem strange but let us explain.

Basically, the term "sonogenetics" means using ultrasound (超声波) to change the behavior of cells in a non-invasive manner. "We already know that ultrasound is safe, and that it can go through bone, muscle and other tissues, making it the ultimate tool for controlling cells deep in the body," says Chalasani.

Low-frequency ultrasound waves can target a particular protein that is sensitive to the signal. This research, published in Nature Communications, focused on TRPA

1. When this protein is stimulated through the ultrasound waves, it also stimulates the cells which carry it. What type of cell is being stimulated depends on the outcome. For example, a muscle cell may contract with stimulation, or a neuron (神经元) in the brain will fire. In this experiment, scientists genetically marked cells with an increased concentration of TRPA1, making them the key targets of the ultrasound waves.

Currently, treating conditions like Parkinson's disease requires scientists to implant electrodes (电极) in the brain which stimulate certain disordered cells. Researchers hope that sonogenetics can one day replace these invasive treatments.

In the future, the team wants to adjust the placement and amount of TRPAI around the body using the gene treatment. Gene delivery techniques have already been shown to be successful in humans, such as in treating blindness. Therefore, it's just a case of adjusting this theory to a different sound-based setting.

"Gene delivery techniques already exist for getting a new gene—such as TRPA1—into the human heart," Chalasani says. "If we can then use an external ultrasound device to activate those cells, that could really change pacemakers." There is still a while to go before this treatment can become a reality. The future for sonogenetics, though, looks bright.

If you've ever emerged from the shower or returned from walking your dog with a clever idea or a solution to a problem you'd been struggling with, it may not be an unusual thing.

Rather than constantly wearing yourself out at a problem or desperately seeking a flash of inspiration, research from the last 15 years suggests that people may be more likely to have creative breakthroughs or insights when they're doing a habitual task that doesn't require much thought — an activity in which you're basically on autopilot. This lets your mind wander or engage in spontaneous cognition or "stream of consciousness" thinking, which experts believe helps recollect unusual memories and generate new ideas.

"People always get surprised when they realize they get interesting, novel ideas at unexpected times because our cultural narrative tells us we should do it through hard work," says Kalina Christoff, a cognitive neuroscientist at the University of British Columbia in Vancouver. "It's a pretty universal human experience."

Now we're beginning to understand why these clever thoughts occur during more passive activities and what's happening in the brain, says Christoff. The key, according to the latest research, is a pattern of brain activity — within what's called the default mode network — that occurs while an individual is resting or performing habitual tasks that don't require much attention.

Researchers have shown that the default mode network (DMN) — which connects more than a dozen regions of the brain — becomes more active during mind-wandering or passive tasks than when you're doing something that demands focus. Simply put, the DMN is "the state the brain returns to when you're not actively engaged," explains Roger Beaty, a cognitive neuroscientist and director of the Cognitive Neuroscience of Creativity Lab at Penn State University. By contrast, when you're trapped in a demanding task, the brain's executive control systems keep your thinking focused, analytical, and logical.

A cautionary note：While the default mode network plays a key role in the creative process, "it's not the only important network," Beaty says. "Other networks come into play as far as modifying, rejecting, or implementing ideas." So it's unwise to place blind faith in ideas that are generated in the shower or during any other period of mind wandering.