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Is Cardio Useless

Is Cardio Useless? Your Brain Says No

Is Cardio Useless

 

As of the timing of this post, I consider myself primarily a weightlifter when it comes to fitness. If you follow my social media posts on Instagram, Twitter, and Facebook you’ll mainly see photos and videos of squats, snatches, cleans, and other movements that involve heavy barbells.

A popular trend in fitness is to condemn forms of exercise called steady-state cardio, which is your classic endurance exercise like long distance running, rowing, cycling, etc. Critics will say steady-state cardio is ineffective for putting on muscle mass and strength as well as a negligible effect on weight loss so it should be discarded as a form of exercise.

Whenever gym bros start talking about cardio

Whenever gym bros start talking about cardio

All of those things are pretty accurate. Cardiovascular exercise has a marginal effect on strength and hypertrophy, and in the absence of diet no form of exercise really promotes weight loss. But this doesn’t mean that cardiovascular exercise is useless. The effect that cardiovascular exercise has on your brain can be life changing.

Cardio and Neurogenesis

Neurogenesis is a term that scientists use to describe the growth of new neurons. For decades it was a widely held belief that all of the brain cells you are born with are the ones that you will have forever. In more recent years, scientists have identified parts of the brain that do produce new brain cells on a regular basis……just a lot more slowly than something like your skin.

One particular region in the brain that is well known to undergo neurogenesis is called the hippocampus.

This little chunk of brain is one of the few areas that can produce new neurons regularly.

This little chunk of brain is one of the few areas that can produce new neurons regularly.

 

The hippocampus is a piece of our brain that is associated with the formation of memories and in learning. It’s been well established in rat studies that neurogenesis happens in this part of the brain, and exercise enhances this process. [Source] But that’s just a rat study. Does this actually happen in humans?

While we can’t put humans on a treadmill for 30 minutes and cut out their hippocampus, there are studies that imply that neurogenesis happens in humans after cardiovascular exercise too [Source]. These studies have showed that exercise improves memory scores, increases the size of the hippocampus, and produces higher amounts of brain derived neurotrophic factor which is the chemical compound associated with neurogenesis.

That’s pretty amazing stuff! This is the type of stuff that helps to explain why people that exercise regularly have a lower risk of dementia. It also helps us understand how exercise can help combat things like ADHD and other brain related disorders.

Does Weight Training Have the Same Impact?

Scientists who did the study on rat brains found that aerobic exercise had double the amount of neurogenesis as sedentary rats. They also found that rats who did resistance exercise had very little effect on the rat brains, even though the rats got physically stronger. Source

Now we have to take that with a grain of salt because:

  1. Rats aren’t people.
  2. The way that the scientists “strength trained” the rats is by tying a weight on their tails and making them climb with it. Not a terribly good comparison to men and women who voluntarily lift weights recreationally.

The biggest take away from this study is the way that aerobic exercise seems to pump up that brain derived neurotrophic factor which may be a key to making your brain grow and heal.

While the effects of weightlifting on neurogenesis hasn’t been studied yet, there is compelling evidence that suggests weight training is beneficial in people with early stages of memory loss. Resistance training has been shown to improve general cognitive performance ¹, improve blood flow to memory areas of the brain ², and save seniors with memory problems money ³.

All Exercise Is Beneficial

At the end of the day, all kinds of exercise is beneficial for different reasons. We have developed a stronger understanding for how cardio can benefit the brain, and there is data that shows that weight training also gives the brain a boost.

There’s no need to shame someone’s exercise of choice. There are so many people that don’t move at all, that anything that a person can do to be active and move regularly will provide them a substantial benefit.

Now if you’re a fitness junkie already, then taking a balanced approach and incorporating something you usually avoid is a great recipe to get the maximum benefits of exercise.

If you are someone that lifts weights 4 days a week without fail, then maybe taking a 2 mile run or row would be a great addition to your weekly regiment. If you run daily and never do strength, then you should definitely look into resistance training to supplement your cardiovascular fitness.

Your brain thrives on exposure to new things.  Beyond some nice looking muscles and better heart health,, the biggest benefit of exercise is making your brain better.

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Young Brains and Football

One Season of Football and the Developing Brain

Young Brains and Football

 

Read Time: [5-6 minutes]

 

2016 continues to be a troublesome year for football as science reveals more information about the effects of repetitive head contact on the brain. It’s pretty well established that concussions can create lasting changes in the structure of the brain, in recent years scientists have sought to study if contact sports can change the brain even without concussion.

Two studies presented this year sought to answer that question, and it looks like football without concussions can still affect a young and developing brain. Here are some links to studies below:

Brain Changes seen in youth football players without concussion

Head impact lead to brain changes in high school football players

Both of these studies had a similar design, but they were performed on different age groups. One was performed on players between the ages of 8-13, the other was performed on high school players. Players were given special helmets to quantify how much head impact they were receiving in practices and in games. The players were also scanned with a special form of MRI called diffusion tensor imaging (DTI) before the season and after the season to see if there were any changes in the structure of the brain after the season.

About DTI

DTI helps to measure structural damage to the brain by helping doctors look at a part of a neuron called an axon. Axons are like power lines of a nerve cell. Whenever a neuron fires, it transmits an electrical signal down these wires so that it can pass the message along to the next neuron in the chain. DTI measures the continuous movement of water through these “wires”.

The resulting image is actually something quite beautiful and remarkable to see. Almost like something you can hang in an art exhibition as you can see below:

 

Image Credit: Google Creative Commons

DTI Image of the axons in the brain. Image Credit: Google Creative Commons

 

One of the things that has been well established is that concussions can damage a lot of the axons in the brain through a process called axonal shearing. It’s basically like a hurricane coming in and knocking down your town’s power lines.

 

Image credit to Artery Studios via Pineterest Arterystudios.com

Image credit to Artery Studios via Pineterest
Arterystudios.com

 

When these axons get damaged, that beautiful DTI image that you saw before hand will start to show some gaps like you see below:

DTI Normal vs Abnormal

Back to Football and Young Brains

So we know that concussions definitely cause axonal injury, but what about all those hits to the head that happen without a concussion? Could they also damage these axons?

According to these 2 recent studies, a year of youth or high school football can make observable changes in the structure of the brain.

The studies also showed that the players who had impacts that were more frequent or more forceful correlated with greater signs of damage.

In high school athletes, the researchers also measured functional changes in the brain and showed that players with greater or more frequent impact showed decreased delta wave activity which is a characteristic sign of brain injury.

So far, not so good.

Imaging Is Not A Death Sentence

So before we draw any conclusions, let’s talk about 2 things.

While we know that these DTI findings are related to concussion and head impact diagnosis, we have no idea if this means anything for the health and quality of life of the patient in the future.

Findings on DTI are NOT predictive of how impaired a patient is, nor does it predict if a patient will have future brain damage or post concussion syndrome. In fact, findings on DTI don’t predict all that much at this point in time.

Obviously we prefer that brains don’t suffer any damage at all, but we do know this:

Most people who suffer head impact and concussions will go on to live normal healthy lives.

Now it’s up to science to figure out how much can someone’s brain take, and how do we take care of these people who are at risk for future brain disease.

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PTSD

Post Traumatic Stress Disorder, Heart Rate Variability, and Brain Resiliance

PTSD

 

Read Time: [6 min]

“The brave men and women, who serve their country and as a result, live constantly with the war inside them, exist in a world of chaos. But the turmoil they experience isn’t who they are; the PTSD invades their minds and bodies.”  – Robert Koger

“You can’t patch a wounded soul with a Band-Aid.” –  Michael Connelly

“Always remember, if you have been diagnosed with PTSD, it is not a sign of weakness; rather, it is proof of your strength, because you have survived!” –  Michel Templet

One of the important things about an election years is that it brings light to topics that rarely see the light of day under normal circumstances. That happened this week as Donald Trump spoke about the need for more mental health resources to help veterans afflicted with PTSD.

“When you talk about the mental health problems, when people come back from war and combat, and they see things that maybe a lot of the folks in this room have seen many times over – and you’re strong and you can handle it – but a lot of people can’t handle it,”

The quote ended up getting taken WAY out of context over the past few days with media outlets saying that “Donald Trump calls soldiers with PTSD weak”. Trump says a lot of things that are polarizing, but I don’t think this was said with an inflammatory intent. It does however highlight the power that words have when discussing health conditions.

Here is the part that I care about: Is PTSD just a matter of mental toughness, or is there something happening physiologically where we can intervene and help make the brain more resilient?

What Happens in the Brain in People with PTSD?

PTSD is a diagnosis with strict criteria, but it’s mainly classified by a patient who routinely relives a traumatic event to the point where it disrupts their normal behavior. This could mean that you have flashbacks, nightmares, or hallucinations from the traumatic episodes. This reliving of an event can lead to avoidance, erratic behavior, depression, and anxiety.

Historically, PTSD has been considered a psychological disorder and despite the mounting evidence to the contrary, psychological disorders carry a stigma of being weak minded.

In more recent years, scientists have been able to identify some real changes in the physical and functional features of the brain. Here’s what we know so far.

  • Shrinkage….of the Hippocampus – MRI studies of patients with PTSD compared to control showed that the memory storing region of the brain is physically smaller. Previous studies have shown that high exposure to the stress hormone cortisol can injure brain cells in the hippocampus.Loss of hippocampal function affects your ability to differentiate between memories and present time events.
  • Hyperactive Amygdala – the amygdala is the seat of emotions in the brain. It is particularly active with intense feelings like fear and sadness. Patients with PTSD have been shown to have increased blood flow to this particular part of the brain
  • Cutting the Breaks - the ventromedial prefrontal cortex is a part of the brain that acts as the CEO of the brain’s emotional response. It serves as the break system to make sure that parts of the brain like the amygdala don’t dominate our experience with purely emotional behavior. In PTSD this part of the brain loses some of the capacity to control the amygdala which allows the Amygdala to become hyperactive.

Heart Rate Variability and the Resilient Body

I love talking about resiliency.

It represents our ability to meet a challenge, survive it, and come out stronger than before.

I’ve always seen the body as a resilient structure. When you are in constant pain or always sick, it’s easy to forget that our bodies are exposed to an insane amount of stress, but it still finds a way to keep us above ground.

One of the most sought after metrics to measure resiliency is a test called Heart Rate Variability or HRV for short. By measuring small differences in the rhythm of your heart beat, HRV gives us an idea of how well your brain controls your organ systems like your heart and intestines.

But that stuff isn’t really that important for your purposes. What you need to know about HRV is that it is an excellent predictor for how resilient your body is to stress and illness.

hrv-1

People with high HRV predict better survival rates for things that put you in imminent danger like cancer, heart attack, and stroke. It can also predict your response to stress, inflammatory response, empathy, and even your recovery from training.

If I had to pick one way to describe HRV, it’s that it is the measurement helps to determine how well your body is going to heal or bounce back.

 PTSD, HRV, and the Brain

We’ve known for a long time and in a lot of studies that people with PTSD have lower HRV. However, we didn’t know if people with lower HRV led to PTSD or if someone getting PTSD led to a lower HRV.

A 2015 study in the prestigious journal JAMA Psychiatry looked to provide some evidence. They studied over 2,000 marines getting deployed into combat. All of the marines had their HRV measured before deployment, and when the marines returned home they were evaluated for PTSD.

The study showed that soldiers with lower HRV had a significantly higher risk of developing PTSD

Now here’s where things get interesting. Remember that part of the brain that acts like the brakes on the brain’s emotional response in PTSD? It’s called the ventromedial prefrontal cortex. As it turns out, this part of the brain is also a big part in the regulation of HRV!

In a 2011 study in the journal Neuroscience and Behavioral Reviews, the authors looked at brain imaging studies and found that HRV is tied to blood flow in the brain in that very same area. When that part of the brain is activated, people have a stronger ability to remain calm and control their emotional responses to stress.

When you have better control over your stress response, you gain control over the health of your body.

Best of All, HRV is Under Your Control

We think about someone’s health and their risk of getting disease, we often associate it to bad luck and bad genes.

The beautiful thing about HRV is that we can readily change our HRV. Things like meditation sleep, biofeedback, exercise, and even chiropractic can stimulate the right part of our brains that can improve our HRV! The reason these things seem to have such an big role in stress management might be because they improve blood flow and activation to the brakes in our brains.

How does the spine affect HRV?

How does the spine affect HRV?

 

In fact, we have been working with some patients on programming ways for people to improve their HRV and seeing how this improves their performance in exercise and overall health. The results so far have been promising.

Now it’s still way too early to say that we should put all of our eggs in the HRV basket. Most studies have identified correlation, and causation is still up in the air. But if we can reliably measure stress using HRV and use these inexpensive, safe, and simple ways to improve your brain’s response to stress, then there’s greater chance that we can help these soldiers start to kick out of the suffering of PTSD.

Talk to Dr. Chung about HRV