My favorite topic to learn about was muscle cramps. For me, this was most surprising. The book cites this as a result of involuntary muscle contractions but it is unclear if it comes from the peripheral nervous system or the central nervous system. For something that is so common-you would think they knew the cause by now! I have always thought that this was a result of dehydration-as I experience leg cramps when I am dehydrated all the time.

But as we have learned, there is not a lot of evidence to link dehydration or electrolyte imbalance to muscle cramps. The book cites that muscle cramps are likely due to changes in the central nervous system. Potential causes of increased motor neuron excitability include high levels of excitatory input to the motor neurons and/or the lack of inhibitory input to the motor neurons. Those promote dysfunction of the muscle spindle and/or the Golgi tendon organ. There are several lines of evidence support the view that exercise can promote dysfunction of muscle sense organs and trigger muscle cramps.

I also enjoyed watching everyone’s presentations (so far). It is always interesting to see where someone takes a topic and what studies they find!

Previously researchers have linked the rise in marijuana use with the lack of exercise across Americans. Angela Bryan, a psychology and neuroscience professor at the University of Colorado Boulder commented that if “the kid on the couch eating Doritos, not being physically active” is the reality of cannabis “that [would be] a big problem”. Previous research has cited that people who use marijuana tend to have lower body mass indexes and decreased risk for obesity than non-users. In 2015, Bryan though her research concluded that “cannabis is linked to greater feelings of motivation and enjoyment about exercise, potentially by activating brain pathways involved in feelings of reward and pain response”.

Now in a new study published by Frontiers in Public Health, Bryan found that many people do use marijuana before and after their workouts. In addition those who do tend to exercise more than the average American. Researches surveyed 600 adult drug users living in the US where marijuana has been legalized. The survey included “when people used the drug, whether they felt it affected their workouts and how they thought it influenced exercise motivation and recovery”.

The results where shocking! More than 80% of the responders used cannabis within an hour of beginning exercise or within four hours after. They reported that marijuana helped them to enjoy exercise more and on average got 2.5 more hours of exercise per week compared to non-users. Bryan says this area needs more research as “It’s not known whether the relationship is causal, for one, and using the drug as a workout aid potentially comes with safety risks”. Because marijuana can disrupt motor functions and increase heart rate, high-intensity exercise may be dangerous.

I thought this article was interesting because it is something different than what others have been writing about. I think this article can be linked to our discussion about pain. Perhaps users can exercise more because marijuana helps to reduce pain associated with exercise. I think more research is required in this field. More detailed tests with subjects performing actually activities versus answering survey questions may show different results. I cannot imagine someone who is high running faster than someone who is not. Even the authors mention “people living in states where marijuana has been legalized, which the study exclusively focused on, happen to be some of the most physically active in the country, so it makes sense that cannabis users there would get a lot of exercise”. It will be interesting to see later studies as marijuana becomes legalized in additional states.

http://time.com/5582780/marijuana-exercise/

I would like to research exercise and how it helps patients with Rheumatoid Arthritis (RA). My mom has had RA for most of my life. She used to run marathons and teach fitness classes. Even when she was first diagnosed she swore by exercise to make her feel better. Now, she does mostly hot yoga and orange theory fitness classes due to the limitations of her arthritis. If she skips a day at the gym she says she can feel it in her joints. I think my presentation could go in a number of directions.

I hope to find out what is the correlation between exercise and RA and in general, what studies that have been done to figure out the science behind this. So far I have found many websites that cite exercise as a way to reduce RA symptoms. But I want to know more about the limitations and how much exercise is too much for RA sufferers. I am also curious to find out of there is correlation between high amounts of exercise in youth/young adulthood that lead to RA. I do not think this is going to turn up many results, as RA does not have any proven causes aside from genetics, but I am interested to find out if there is some correlation.

Others should be interested in my topic because exercise has an effect on many different types of diseases, not just RA. Though RA currently effects about 1.3 billion Americans, this presentation may spark your interest to research more into how other diseases correlate with exercise.

So far I have found many studies on therapeutic exercises for RA sufferers. These are mostly focused on pain felt by those doing moderate aerobic exercises to those not. I have also found articles that look at intense verses light exercise on subjects with RA. Most of the articles state that exercise is all around beneficial and does not speed the disease.

The benefits of lactic acid accumulation in muscle cells has been recently debated. Scientists arguing that lactic acid is “the latest performance-enhancing drug” have drawn false conclusions by over interpretation of their data (Lindinger). In “Point:Counterpoint: Lactic acid accumulation is an advantage/disadvantage during muscle activity” a series of debates took place within the Journal of Applied Physiology in search of the truth behind the benefits of Lactic acid accumulation. Jens Bangsbo and Carsten Juel of Copenhagen Muscle Research Center and the University of Copenhagen argue that “, the negative consequences of lactic acid accumulation far exceed any positive effects” (Lindinger). Multiple studies on lactic acid production in humans have linked elevated lactate levels to higher pH in muscle cells. In one study, after completing an arm exercise, subjects were able to perform a subsequent leg exercise at about 75% compared to controls (Lindinger). In experiments with animal models, muscles incubated in lactic acid that underwent repeated exhaustive stimulation showed faster fatigue development (Lindinger). In an experiment with isolated dog muscle, lactate ion perfusion reduced muscle twitch force by 15% (Lindinger). Most experiments conclude that lactate acid effects are associated to the function of the muscle membrane and not the skinned muscle fibers. Other studies have linked lactic acid formulation with impaired performance of Ca²⁺ release channels (Lindinger).

Evidence also suggests lactic acid production plays a role in conveying fatigue related information to the brain (Ishii). In one study eleven healthy adults performed hand grip exercises at varying intensities for 120 seconds. The exercises caused significant fatigue while their brain activity increased at 30% and 50% maximal voluntary contraction (Ishii). Blood lactate and flow rates also increased during the study; most notably at these percentages. The authors through analysis were able to conclude that these two factors may convey load intensity to the brain during fatigue (Ishii).

Ishii, Hideaki, and Yusuke Nishida. “Effect of Lactate Accumulation during Exercise-induced Muscle Fatigue on the Sensorimotor Cortex.” Journal of physical therapy science vol. 25,12 (2014): 1637-42. doi:10.1589/jpts.25.163

Lindinger, Michael Ivan. “Lactic Acid Accumulation Is an Advantage/Disadvantage during Muscle Activity.” Journal of Applied Physiology, vol. 100, no. 6, 2006, pp. 2100–2102., doi:10.1152/japplphysiol.00213.2006.

1. Over the last four years, I have developed a passion for exercising. The love of exercise I now have is my most cherished accomplishment. In high school I played multiple sports and was constantly consumed with practice. Here at Union over the past four years, I have been able to focus on myself at the gym. I have had more time to find out what I like to do and what works for me. I am very proud of how much I’ve grown, since coming to college in my love for exercise. Though I have only increased my running speed by about half a mile per hour, I genuinely enjoy running. This is something I never thought was possible. I am very happy when I enter the gym. At school, I have found the other benefits in exercise. I use it to clear my mind, take a break from my homework and spend some time alone. I cannot pin it down to one day at the gym or one moment in my head, but looking back over how I viewed exercise when I entered Union to how I view it now, I am very happy that I have developed a noticeable joy. I hope this desire to get to the gym everyday is something I take with me for the rest of my life!
2. I think exercise physiology can serve as a paradigm for understanding biology because it encompasses a variety of topics. In doing the readings for this class, I have already reviewed a lot of the material covered in previous molecular and cellular biology courses. One aspect of exercise physiology is the chemical process-taking place within the body that makes exercise possible. Another topic covered in exercise physiology could be evolution. It is important to understand animal fitness and why organisms have developed the way they have. An organism’s structure, physiology, is an important aspect of it fitness and therefore how predominantly they evolve. I think exercise physiology can also serve as a paradigm for biology because it focuses on something relatable. I think exercise is easy to conceptualize. Everyone has exercised at some point in their life and understands how that makes the body feel therefore it is an interesting topic of study. Using exercise physiology as a model for biology I think helps students to better understand complicated concepts.
3. One upper-level course I recently finished was Evolutionary Biology. In this class we focused on means of evolution as well as fitness in organisms. From this class I hope to contribute knowledge of animal structure and how that may contribute to their fitness. One case study we focused on was the evolution and breeding of horses. We learned that humans have artificially selected for horses that can run faster. Through studies they have determined that horses with longer legs and larger hearts are able to run at greater speeds. We learned that these greater running mechanisms can also have negative aspects on the rest of the body. Another upper-level course I took was Orthopedic Biomechanics. In this class we focused on bone and joint structure. From this class I hope to contribute my knowledge of human bone structure and how different joints may be affected during different durations or types of exercise.