In a study published today in the British Journal of Sports Medicine, the researchers say that 11 minutes a day (75 minutes a week) of moderate-intensity physical activity — such as a brisk walk — would be sufficient to lower the risk of diseases such as heart disease, stroke and a number of cancers.

Cardiovascular diseases — such as heart disease and stroke — are the leading cause of death globally, responsible for 17.9 million deaths per year in 2019, while cancers were responsible for 9.6 million deaths in 2017. Physical activity — particularly when it is moderate-intensity — is known to reduce the risk of cardiovascular disease and cancer, and the NHS recommends that adults do at least 150 minutes of moderate-intensity activity or 75 minutes of vigorous-intensity activity a week.

To explore the amount of physical activity necessary to have a beneficial impact on several chronic diseases and premature death, researchers from the Medical Research Council (MRC) Epidemiology Unit at the University of Cambridge carried out a systematic review and meta-analysis, pooling and analysing cohort data from all of the published evidence. This approach allowed them to bring together studies that on their own did not provide sufficient evidence and sometimes disagreed with each other to provide more robust conclusions.

In total, they looked at results reported in 196 peer-reviewed articles, covering more than 30 million participants from 94 large study cohorts, to produce the largest analysis to date of the association between physical activity levels and risk of heart disease, cancer, and early death.

The researchers found that, outside of work-related physical activity, two out of three people reported activity levels below 150 min per week of moderate-intensity activity and fewer than one in ten managed more than 300 min per week.

Broadly speaking, they found that beyond 150 min per week of moderate-intensity activity, the additional benefits in terms of reduced risk of disease or early death were marginal. But even half this amount came with significant benefits: accumulating 75 min per week of moderate-intensity activity brought with it a 23% lower risk of early death.

Dr Soren Brage from the MRC Epidemiology Unit said: “If you are someone who finds the idea of 150 minutes of moderate-intensity physical activity a week a bit daunting, then our findings should be good news. Doing some physical activity is better than doing none. This is also a good starting position — if you find that 75 minutes a week is manageable, then you could try stepping it up gradually to the full recommended amount.”

Seventy-five minutes per week of moderate activity was also enough to reduce the risk of developing cardiovascular disease by 17% and cancer by 7%. For some specific cancers, the reduction in risk was greater — head and neck, myeloid leukaemia, myeloma, and gastric cardia cancers were between 14-26% lower risk. For other cancers, such as lung, liver, endometrial, colon, and breast cancer, a 3-11% lower risk was observed.

Professor James Woodcock from the MRC Epidemiology Unit said: “We know that physical activity, such as walking or cycling, is good for you, especially if you feel it raises your heart rate. But what we’ve found is there are substantial benefits to heart health and reducing your risk of cancer even if you can only manage 10 minutes every day.”

The researchers calculated that if everyone in the studies had done the equivalent of at least 150 min per week of moderate-intensity activity, around one in six (16%) early deaths would be prevented. One in nine (11%) cases of cardiovascular disease and one in 20 (5%) cases of cancer would be prevented.

However, even if everyone managed at least 75 min per week of moderate-intensity physical activity, around one in ten (10%) early deaths would be prevented. One in twenty (5%) cases of cardiovascular disease and nearly one in thirty (3%) cases of cancer would be prevented.

Dr Leandro Garcia from Queen’s University Belfast said: “Moderate activity doesn’t have to involve what we normally think of exercise, such as sports or running. Sometimes, replacing some habits is all that is needed. For example, try to walk or cycle to your work or study place instead of using a car, or engage in active play with your kids or grand kids. Doing activities that you enjoy and that are easy to include in your weekly routine is an excellent way to become more active.”

The research was funded by the Medical Research Council and the European Research Council.

What counts as moderate-intensity physical activity?

Moderate-intensity physical activity raises your heart rate and makes you breathe faster, but you would still be able to speak during the activity. Examples include:

• Brisk walking
• Dancing
• Riding a bike
• Playing tennis
• Hiking

John Bates, the senior author of a new study in the journal Royal Society Open Science reporting on the hybrid, first encountered the unusual bird while doing fieldwork in Peru’s Cordillera Azul National Park, which protects an outer ridge on the eastern slopes of Andes mountains. Since the area is isolated, it would make sense for a genetically distinct population to emerge there. “I looked at the bird and said to myself, ‘This thing doesn’t look like anything else.’ My first thought was, it was a new species,” says Bates, a curator of birds at Chicago’s Field Museum.

When Bates and colleagues gathered more data about the specimen in the Field Museum’s Pritzker DNA Lab, however, the results surprised everyone. “We thought it would be genetically distinct, but it matched Heliodoxa branickii in some markers, one of the pink-throated hummingbirds from that general area of Peru,” says Bates. If it was H. branickii, it didn’t make sense for the bird to have gold throat feathers; in the hummingbird family, it’s rare for members of the same species to have dramatically different throat colors.

The initial run of DNA sequencing looked at mitochondrial DNA, a type of genetic material that only gets passed down through the mother. That mitochondrial DNA gave a clear result matching H. branickii; the researchers then analyzed the bird’s nuclear DNA, which includes contributions from both parents. This time, the DNA showed similarities to both H. branickii and its cousin, H. gularis. It wasn’t half branickii and half gularis, though — one of its ancestors must have been half-and-half, and then later generations mated with more branickii birds.

The question remained how two pink-throated bird species could produce a non-pink-throated hybrid. The study’s first author, Field Museum senior research scientist Chad Eliason, says the answer lies in the complex ways in which iridescent feather colors are determined.

“It’s a little like cooking: if you mix salt and water, you kind of know what you’re gonna get, but mixing two complex recipes together might give more unpredictable results,” says Eliason. “This hybrid is a mix of two complex recipes for a feather from its two parent species.”

Feathers get their base color from pigment, like melanin (black) and carotidnoids (red and yellow). But the structure of feathers’ cells and the way light bounces off them can also produce something called structural color. Color-shifting iridescence is a result of structural color.

The researchers used an electron microscope to examine the throat feather structure on a subcellular level, and an analytical technique called spectroscopy to measure how light bounces off the feathers to produce different colors. They found subtle differences in the origin of the parents’ colors, which explain why their hybrid offspring produced a totally different color.

“There’s more than one way to make magenta with iridescence,” says Eliason. “The parent species each have their own way of making magenta, which is, I think, why you can have this nonlinear or surprising outcome when you mix together those two recipes for producing a feather color.”

While this study helps explain the strange coloration of one unusual bird, the researchers say that it opens the door to more questions about hybridization.

Separate species are generally defined as lineages that are genetically distinct and don’t interbreed with each other; hybrids break that rule. Sometimes hybrids are weird one-offs or are sterile, like mules; in other cases, hybrids can form new species. It’s not clear how common hummingbird hybrids like the one in this study are, but the researchers speculate that hybrids like this one might contribute to the diversity of structural colors found across the hummingbird family tree.

“Based on the speed of color evolution seen in hummingbirds, we calculated it would take 6-10 million years for this drastic pink-gold color shift to evolve in a single species,” says Eliason.

Co-author Mark Hauber at the University of Illinois Urbana-Champaign adds that “this study gives us clues about the nanostructural basis of evolutionary shifts in color.”

This study was contributed to by Bates’s and Eliason’s Field Museum colleagues Jacob Cooper (now at the University of Kansas), Shannon Hackett, Erica Zahnle, Dylan Maddox, and Taylor Hains, as well as Tatiana Paqueño Saco (Peruvian Ministry of Natural Resources) and Mark Hauber (University of Illinois, Urbana-Champaign).

The onset of DLB is associated with abnormal deposits of alpha-synuclein, a protein in the brain that plays a role in the transmission of signals between neurons. The presence of these deposits, known as ‘Lewy bodies’, affects chemicals in the brain, leading to declines in thinking, reasoning and memory. Symptoms include confusion, memory loss, impaired movement, and visual hallucinations.

Parkinson’s disease also starts with movement problems, but some patients develop cognitive decline within one year. These patients are diagnosed with DLB when this cognitive decline occurs. Physicians find it difficult to predict which people with Parkinson’s disease will develop cognitive decline within a year and become patients with DLB.

A research group led by Associate Professor Masaaki Hirayama (Omics Medicine), Professor Kinji Ohno (Neurogenetics), and Assistant Professor Hiroshi Nishiwaki (Neurogenetics) of Nagoya University Graduate School of Medicine, in collaboration with Okayama Neurology Clinic, Iwate Medical University, and Fukuoka University, analyzed microorganisms in the gut and fecal bile acids of patients with DLB, Parkinson’s disease, and rapid eye movement behavior disorder. They discovered that three intestinal bacteria, Collinsella, Ruminococcus, and Bifidobacterium, were associated with patients with DLB. This may suggest possible ways of diagnosing and treating this neurodegenerative disease.

The researchers also found similarities between the gut bacteria involved in Parkinson’s disease and DLB. In both diseases, the bacteria Akkermansia, which degrades the intestinal mucosa, increased. On the other hand, the bacteria that produce short-chain fatty acids (SCFA) in the gut decreased. “Decreases in SCFA-producing bacteria have been repeatedly reported in Parkinson’s disease, Alzheimer’s disease, and ALS,” explains Ohno. “This suggests that it is a common feature of neurodegenerative diseases.” SCFA are important because they produce regulatory T cells. These types of cells play a critical role in regulating the immune system by suppressing neuroinflammation.

On the other hand, in patients with DLB, the researchers found an increase in Ruminococcus torques, an increase in Collinsella, and a decrease in Bifidobacterium. This was different from Parkinson’s disease patients, whose levels did not change. In the future using these insights, doctors may be able to analyze the bacteria in a person’s digestive tract to distinguish DLB from Parkinson’s disease.

Importantly, the reduced levels of Bifidobacterium mayalsosuggest possible ways to treat DLB. Bifidobacterium increases brain-derived neurotrophic factor, a key protein that supports the growth, development and maintenance of neurons in the central and peripheral nervous systems. Therefore, its decrease in DLB is likely to be associated with cognitive decline.

Similarly, both Ruminococcus torques and Collinsella are intestinal bacteria that carry an enzyme, the product of which regulates inflammation in a region of the brain called the substantia nigra.The substantia nigra produces dopamine, a neurotransmitter that is involved in the regulation of movement and is deficient in Parkinson’s disease. Compared to Parkinson’s disease, the levels of these bacteria were higher in people with DLB. This may explain why the effect on movement is delayed, a key feature that distinguishes DLB from Parkinson’s disease.

“Our findings can be used both for both diagnosis and treatment,” explains Ohno. “If a patient with Parkinson’s disease develops dementia in one year after the onset of motor symptoms, they are diagnosed with DLB. However, we cannot currently predict whether a patient with Parkinson’s disease will become a DLB patient. The gut microbiome will help to identify such patients.”

“In terms of treatment, the administration of Ruminococcus torques and Collinsella in patients with Parkinson’s is expected to delay neuroinflammation in the substantia nigra,” Ohno added. “Therapeutic intervention to increase Bifidobacterium may delay the onset and progression of DLB and reduce cognitive dysfunction.”

“The presence of intestinal bacteria unique to DLB may explain why some patients develop Parkinson’s disease and others develop DLB first,” Ohno said. “Normalizing the abnormal bacteria shared between DLB and Parkinson’s disease may delay the development of both diseases. Improving the gut microbiota is a stepping stone in the treatment of dementia. Our findings may pave the way for the discovery of new and completely different therapeutics.”