Life Lines by Dr. Dolittle

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Diet and Exercise

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How exercise training and diet may impact exercise performance

Both diet and exercise training are associated with muscle performance and endurance. Migratory birds undergo intense endurance exercise. In fact, a recent review indicated that flapping flight costs more energy (9 x increase from basal metabolic rate) than required by elite athletes competing in the Tour de France (4.3 x increase from basal metabolic rate) (Butler, 2016). Unlike running animals, migratory birds fuel endurance exercise with fats as opposed to […]

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Take Time for Activity Snacks

There went another day spent sitting at my computer in virtual meetings with easily accessible snacks in the kitchen nearby. Okay, granted this is not a comparative physiology topic. But it is something many of us can relate to in this age of Covid-19. In a new study published in the Journal of Applied Physiology, researchers explored what happens when people seek out so-called “activity snacks” instead of the salty […]

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Extreme Fasting

While giant pandas roll in horse manure to stay warm in the winter (that’s a different story), other animals spend up to 8 months hibernating to conserve energy during times of reduced food availability and freezing temperatures. During their long winter’s nap, animals such as the Arctic ground squirrel and 13-lined ground squirrel go without food or water while at the same time avoiding muscle wasting – a rather impressive […]

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The evolution of sugar addiction

I have been opening Christmas cards and pondering the science of sugar addiction, admittedly while snacking on sugar cookies – ‘tis the season after all! Excess consumption of highly palatable (i.e. quite tasty) foods as well as sedentary lifestyles are thought to be at the root of the current obesity epidemic. In fact, it is thought that as many as 30% of people living in developed countries are either overweight […]

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Speaking of space…’Mighty Mice’ stay mighty muscular in space

While we are on the topic of research conducted by astronauts on the International Space Station (ISS), Space X’s 19th resupply mission to the ISS included studies that might help prevent muscle loss in astronauts as well as humans on Earth. While exercise programs have been developed for astronauts, these programs may not be as useful for long-distance space travel – such as a trip to Mars. This is where […]

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Extreme flight

May I have a drumroll please? The winner is…..the bar-tailed godwit!! *round of applause!!!!* The winner of what you may ask? This bird broke the world record for the longest non-stop flight – 7,500 miles – without the luxury of in-flight service. I bet it was hungry when it landed…

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Sex differences in eating after exercise

Diet and exercise are regarded as the most effective means to maintain weight as well as lose weight. But, there’s sometimes a catch as their effectiveness varies between individuals. Moreover, many people find it really difficult to keep the weight off. Researchers think this may happen in part because the body adapts to weight loss by increasing appetite and decreasing energy expenditure. Here is where exercise, in particular, is thought […]

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Avian red blood cells produce hydrogen sulfide to maintain cell integrity and longevity

Birds have strange red blood cells, at least in comparison to mammals. While they both are responsible for transporting oxygen molecules throughout the body, avian red blood cells have mitochondria and a nucleus. Mammalian red blood cells, on the other hand, are missing a nucleus as well as organelles. By eliminating these structures, mammalian red blood cells are able to carry more oxygen molecules and fold more easily to fit […]

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Hypoxia improves exercise duration

Speaking of hypoxia, a new study published in Physiological Reports examined how training for 2 weeks under 18% hypoxia impacts muscles of Thoroughbred horses. Unlike humans, these horses do not increase production of red blood cells to enhance oxygen transport throughout the body under hypoxic conditions. This difference led researchers to speculate that the horses had other ways of adapting to exercise.   In the new study, horses were trained […]

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Physiology of diving animals: how do they deal with hypoxia?

Dr. Jose Pablo Vazquez-Medina (pictured at right), a comparative physiologist at the University of California – Berkeley, was scheduled to present several ongoing studies from his lab at the Experimental Biology conference last month. Dr. Vazquez-Medina is a member of the Comparative and Evolutionary Physiology section of the American Physiological Society. Although the conference was cancelled due to Covid-19, Dr. Vazquez-Medina has agreed to share his research with us.   […]

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