How to Lubricate Your Body’s Gears
You have gears in your spine. Ask these Swedish researchers who say so, and learn some gear maintenance skills, too.
Make Like a Locomotive
How do signals travel down your spine to activate your muscles? According to Medical Xpress, scientists at the Karolinska Institute have revealed a “locomotor engine” in the spinal cord that acts like a set of gears.
Researchers at Karolinska Institutet in Sweden have revealed a new principle of organization which explains how locomotion is coordinated in vertebrates akin to an engine with three gears. The results are published in the scientific journal Neuron.
A remarkable feature of locomotion is its capacity for rapid starts and to change speed to match our intentions. However, there is still uncertainty as to how the rhythm-generating circuit—the locomotor engine—in the spinal cord is capable of instantaneously translating brain commands into rhythmic and appropriately paced locomotion.
They found something in experiments on zebrafish that are “directly applicable to mammals,” they claim. It’s “intuitively simple” yet crucial for our ability to get into gear when our brain tells the spinal cord to get moving.
The researchers performed a comprehensive and quantitative mapping of connections (synapses) between neurons combined with behavioral analyses in zebrafish. The results revealed that the excitatory neurons in the spinal cord which drive locomotion form three recurrent, rhythm-generating circuit modules acting as gears which can be engaged at slow, intermediate or fast locomotor speeds. These circuits convert signals from the brain into coordinated locomotor movements, with a speed that is aligned to the initial intention.
It’s a marvel of mind over matter. You decide to move, and the spinal cord gets into gear. Like a genie serving its master, your wish is its command!
Human bodies prefer feet on the ground. Physiologists for astronauts know that the longer a human body stays in space, the weaker it gets because of “osteopenia,” or bone mass loss from decreasing mineral density, caused by the body’s response to weightlessness. The record for time in space is shy of a year (CollectSpace.com). Usually, astronauts returning to Earth after lengthy times in space cannot even stand up without help, and require significant recovery time to adjust back to Earth gravity. Astronauts chosen for future missions to Mars will suffer even more, because round-trip missions are estimated to take three years.
A team funded by the Bill and Melissa Gates Foundation is working to estimate the amount of osteopenia astronauts would suffer on a mission to Mars. Their paper by Axpe et al., “A human mission to Mars: Predicting the bone mineral density loss of astronauts,” was just published in the open-access journal PLoS One. (Gates is a strong believer in open science.) The team issued their current predictions for what will happen to the bones of Mars astronauts.
There is an urgent need to understand BMD [bone mineral density] progression as a function of spaceflight time to minimize associated health implications and ensure mission success. Here we introduce a nonlinear mathematical model of BMD loss for candidate human missions to Mars: (i) Opposition class trajectory (400–600 days), and (ii) Conjunction class trajectory (1000–1200 days). Using femoral neck BMD data (N = 69) from astronauts after 132-day and 228-day spaceflight and the World Health Organization’s fracture risk recommendation, we predicted post-mission risk and associated osteopathology. Our model predicts 62% opposition class astronauts and 100% conjunction class astronauts will develop osteopenia, with 33% being at risk for osteoporosis. This model can help in implementing countermeasure strategies and inform space agencies’ choice of crew candidates.
This is just for bone mass problems. As we have reported before, exposure to radiation from cosmic rays and the solar wind will take additional tolls on the astronauts’ health, possibly leading to cancer or dementia [23 Sept 2006].
Lubricating Your Gears
Learning about our bodies’ amazing designs should motivate us to care for them. Part of that care involves exercise (more on that tomorrow); an equally important part is diet. Many who make New Year’s resolutions to improve their fitness are confronted with ads for protein shakes. Do they do any good? At The Conversation, sports nutrition expert David Rogerson provides some science-based advice to answer a common question: “Protein powder, shake, and supplement: how much can our body actually use?”
Protein is an essential nutrient that we can’t live without. Every cell in our body contains protein. We use it to build and repair tissues, as source of energy, and to make hormones and enzymes. But people might also use protein – often in the form of supplements – to help with gaining muscle, losing weight, and to optimise their workouts by improving performance and recovery. Consuming extra protein has even been shown to increase muscle development and strength when consumed as part of an exercise programme.
Having established that protein is an essential food for everyone, especially those who want to build muscle, Rogerson questions whether protein shakes, which usually contain whey powder, are really necessary. It’s possible they act too quickly and return protein levels to normal levels within a couple of hours (excess protein is excreted). Dietitians know fairly well how much protein needs to be consumed each day for the body’s needs, proportional to body weight; more protein is required during vigorous exercise to build muscle. But timing of protein consumption is also important. Protein-rich foods in the diet should be preferred, he says; they may keep amino acids in the blood available longer than protein shakes do. Nevertheless, Rogerson admits that the science is not settled. “So, do we really need protein supplements to get fit and look good? Well, probably not, as experts recommend we consume whole-food sources wherever possible,” he concludes. “But if the protein supplement allows you to meet your daily protein needs, then it probably won’t hurt.”
Another dietary tip comes from Penn State: “Walnuts may be good for the gut and help promote heart health.” These tasty nuts can be added to many foods or eaten whole. The scientists describe what they do for us, and give recommendations. Evolution News published a really interesting article about the many beneficial uses of walnuts for health and much more. They have some of the toughest seed coats of any nut. How they build them is quite a study in engineering design that materials scientists are trying to imitate. Read the article to learn why walnuts exhibit “intelligent design in a nutshell – literally.”
Of all people, creationists should be the most interested in physical fitness. Why? It’s an expression of worship and gratitude to our Maker. The more we learn about the marvels going on in our bodies, from the molecular level to the whole person, the more we should stand in awe of what God has given us. If the owner of a Ferrari would treat it like a treasure, how much more should we attempt to keep our bodies in peak condition? Even if we don’t have the endowments of top athletes, or the time to invest in training that they have, we can try better with what we have. Creationism is good for every body.