Wednesday, March 28, 2018

Optimal Performance Weight For Endurance Athletes

Using total body weight alone is
like the cover of a text book.  It
gives you some idea of what's
inside but lacks important detail.
 "Never be fooled by what you see on the outside because on the inside it's often a different story." ~Anonymous
Human performance results from a complex interaction of physical, psychological, and nutritional variables. Your "optimal performance weight" is one of those variables. Let's drill down a little deeper into the topic.
Optimal Performance Weight
Body weight is an incredibly sensitive topic to discuss. Various societal pressures have increased the prevalence of disordered eating and exercise behaviors in young people. Some estimates suggest there are approximately 30 million US adults struggling with an eating disorder with 95% of them between the ages of 12-25. Female athletes make up a disproportionate percentage of that group. Many endurance athletes have experienced an eating disorder before or perhaps are struggling with one now. It is for that reason that I approach this subject very cautiously and in the spirit of supportive guidance rather than with disapproving judgement.

Body weight is inextricable related to endurance performance. More specifically, body composition (lean body mass and fat mass) is linked to endurance performance. But no online "optimal performance weight" calculator can determine that for you. Your optimal performance body composition can only be determined by consistent data collection over time. Here's how it works.

Body Composition
Your total body weight alone is like the cover of a text book; it gives you some idea of what's inside but lacks important details. With respect to body composition those details include lean body mass and percent body fat. If you're interested in optimizing endurance performance you should consider measuring your body composition routinely. These periodic body composition assessments create body accountability and data points. When assessing body composition consider the following guidelines;

1.) Assess Monthly
More frequent assessment is less sensitive to actual changes in body composition and more sensitive to daily or weekly fluctuations in body water.

2.) Standardize
By creating the same testing conditions (time of day, clothing, etc) you significantly reduce the error associated with the testing conditions.

3.) Testing Considerations
When you test make sure that you haven't exercised or eaten for at least three hours prior to the assessment and always on an empty bladder and bowel (ideally).

Commercial body fat scales are now both widely available and affordable. Most use "bioelectric impedance" technology which has been around for decades and highly correlated with the gold standards for this procedure (skinfold and plethysmography).

Performance Outcomes
Once you are in the habit of collecting lean body mass and percent body fat data the next step is to correlate it to endurance performance. There are a few important things to consider. First, understand that body composition naturally fluctuates throughout the year and/or training cycle. Differences in eating and activity patterns during the winter months and off-seasons tend to result in natural and acceptable increases in percent body fat during these times. Secondly, we must always account for the effects of aging on both performance and body composition. That is to say, you should keep your comparison of body composition and performance to the last 3-5 years. Anything beyond that becomes an unreasonable and unrealistic comparison and sets you up for discouragement and resultant demotivation. Lastly, standardize the correlation by choosing an event or workouts that is both relevant and repeatable.

My Experience
The last four years of body fat and Orchard Cross
results clearly shows that for me; leaner is faster.
This graph is the last four years of my percent body fat and cyclocross performance. The body composition data was collected on a Tanita body fat scale once a month (I've actually been collecting the data monthly for over a decade). The performance data is from a local cyclocross race (Orchard Cross) that I've done for a number of consecutive years and represents the finish points in my Category 4/5 40+ race. For those not familiar with cyclocross, the lower the finish points the better the performance relative to the rest of the field. There are a few important things to note from the graph. The first is that you can clearly see seasonal fluctuations in percent body fat with the winter months generally representing the higher percent body fat values. Secondly, there appears to be a direct correlation to my percent body fat and my Orchard Cross results. In other words, the lower my percent body fat, the better the performance result (in lower points) at that specific race. While this really isn't a surprise, it's very helpful for me to see it in black and white (and red). This graph clearly demonstrates that my 50 year old optimal performance body composition is around 10% body fat. And just as importantly, I know exactly the dedication it takes to reach this level.

Please remember that this value is highly individualized. Your optimal performance body composition is uniquely yours and you must collect adequate amounts of data to determine that value.

Tuesday, March 20, 2018

Spring Cleaning Tips For Endurance Athletes

"The best way to find out what we really need is to get rid of what we don't."  -Marie Kondo

Spring cleaning is the common practice of giving your home and property a thorough tidying at the end of Winter.  It's also a great time to identify and correct minor, seasonal problems that could end up causing more significant issues, frustration, and expenses down the road.  While this is the perfect time to dust the furniture, it's also a great time to metaphorically "dust" your training program.  Here are the Top 5 Spring Cleaning Tips For Endurance Athletes.

#1:  Stop Trying
It's been said that "trying is lying".  When our response to a challenge is "to try" we create an outcome vagueness that gives us an excuse for coming up short.  Subconsciously we have already determined that we won't make it, and when we don't it really won't be our fault.  The "trying" mindset focuses critical attention on unknown factors that potentially prevent you from attaining your goal.  Don't "try", rather intend to commit yourself fully to the challenge by engaging the process with effort.  Effort is something that is applied, not tried.1

#2:  Slow Down
One of the most common mistake endurance athletes make is performing their "active recovery" training units too hard.  Training intensity may be monitored using heart rate, pace, or power.  Active recovery units are designed to add sport-specific training volume and enhance maximum lactate steady-state by increasing Type 1 skeletal muscle fiber function without the cardiovascular and musculoskeletal stress.  For optimal benefit these training units should be performed at less than 85% of threshold heart rate, pace, or power.  

#3:  Tighten Up
Strength training is critical to performance for endurance athletes.  It's fairly easy to get to the gym during the long cold dark winter months but as the daylight hours lengthen and the weather warms up we tend to commit ourselves less to the practice.  It's reasonable to reduce the volume of training in the gym as the amount of sport-specific activities increase, just make sure you are still performing a total body routine at least twice a week.  If on the other hand you haven't been to the gym in months, now is a great time to commit yourself once again.

#4:  Cut Back
Every endurance athlete has an optimal performance-based body weight.  Very few of us are at that weight at the beginning of Spring.  Too little time spent outdoors in the wintertime may result in a relative Vitamin D deficiency.  This can often lead to seasonal disturbances in mood.  These seasonal mood disturbances may cause us to seek out comfort foods like sweets and alcohol in an effort to balance brain chemistry.  The result is that we are often a few pounds from that optimal performance-based weight.  An excellent first step toward that goal is to cut back on two sources of empty calories including sweets and alcohol.  While eliminating them may be unrealistic for many endurance athletes, cutting back by avoiding during the week saves significant calories and often leads to positive changes in body composition.  

#5:  Find Balance...Again
Our love of endurance sports is one way we define ourselves.  Yet sometimes it becomes painfully obvious that our training and racing doesn't happen in a vacuum.  The stark reality is that our training and racing happens in the context of the rest of our lives.  Our very busy lives.  In this age of social media-based training communities it's easy to caught up in what everyone else is doing.  This often leads to us feeling insecure about the amount of training we are doing and causes us to overextend ourselves.  When the delicate balance of training and "life" is upset, our training is often sacrificed.  Now is a great time to sit down and sketch out a training plan that fits your life, rather than your life fitting your training plan.  When endurance athletes have it the other way around, it's only a matter of time that this "house of cards" comes crashing down.  

1 The Rock Warrior's Way by Arno Ilgner

Tuesday, March 13, 2018

Supraventicular Tachycardia & Endurance Athletes

Endurance athletes live longer
than non-athletes but are at
greater risk of heart abnormalities.
Photo from VeloNews.
"Follow your heart but take your brain with you." ~Anonymous
In the field of exercise science there is a concept known as The Exercise Paradox and it suggests that if you survive enough repeated bouts of exercise you'll likely outlive those who never exercise. While that sounds dramatic, the facts are that as exercise intensity increases so does the risk of bad things happening. And almost all of those things involve the heart. But the flip side is the adoption of exercise a lifestyle behavior significantly reduces the risk of hypokinetic early mortality-related diseases like heart disease, diabetes, obesity, and certain site specific cancers. Recent evidence suggests that masters endurance athletes with a long history of training may be at increased risk of heart-related rhythm abnormalities including one called supraventricular tachycardia. And as luck would have it, I recently discovered I too have experienced it.
In a previous career I spent nearly 25 years as a clinical exercise physiologist and had the good fortune to supervise over a million person-hours of ECG-monitored exercise. It's fair to say this particular topic is in my wheelhouse. I also was witness to countless episodes of this phenomena in the patients I supervised.
Heart Rate Monitoring
Many endurance athletes collect heart rate data during training. The consumer version of the technology has become quite advanced, accurate, and much more commonplace in the last 20 years. The most popular versions include wireless chest strap and wrist-based monitors. Although my personal bias is toward the chest-strap technology, recent comparative reviews have shown that both technologies are reasonably well correlated if the manufacturers instructions are followed. For nearly all of us who add the technology and data to our training plans, the motivation is to add important detail with respect to cumulative training stress across all modalities. But the benefits should also include the possibility of uncovering one of the more common and perhaps most elusive heart rhythm disturbances in endurance athletes; supraventricular tachycardia.

Supraventricular Tachycardia (SVT): What You Need To Know
Supraventricular tachycardia occurs when faulty electrical connections in the upper chambers of the heart (ie. atria, "supraventricular", or above the ventricles) trigger and sustain an abnormal rhythm. When this happens, the heart rate accelerates (ie. tachycardia) too quickly and doesn't allow enough time for the heart to fill before it contracts again potentially impacting it's performance.(1)
This heart rhythm abnormality is one of the more common found in endurance athletes and is generally categorized as a "tachyarrhythmia" (ie. fast abnormal heart rate).  It often manifests itself as a sudden unpredictable accelerated heart rate (150-200 beats/minutes) that is inconsistent with the amount of exercise performed, is sustained for a number of minutes, and often resolves spontaneously.  Endurance athletes are largely desensitized to the feeling of high heart rates, so it may go unnoticed (ie. without symptoms).  However, some individuals are symptomatic while it is happening describing symptoms such as a fluttering in the chest, abnormal shortness of breath, dizziness, or unusual exercise-associated anxiety.  These symptoms and this abnormal rhythm may last for minutes or days and should result in a visit to your healthcare provider.  If you experience these symptoms associated with a sudden onset of accelerated heart rate inconsistent with the amount of activity performed you may be able to "break" the arrhythmia by using the valsalva maneuver.  Sit down and expire forcefully against a closed glottis for a few seconds.  This "bearing down" can momentarily alter the electrical pathways in the heart and resolve the arrhythmia.

Practical Application: How It's Uncovered
If the abnormal heart rhythm goes unnoticed it may not be until the post-activity review of the training data that the unusual accelerated heart rate is discovered. If endurance athletes notice this unusual accelerated heart rate the first thing that must be ruled out is a malfunction in the heart rate monitor itself. While home-based heart rate monitoring technology is robust, it is not without error. Generally speaking, if you notice sudden brief "spikes" in heart rate lasting only a few seconds it can be assumed that it is an equipment error. However, if these accelerated heart rates are sustained for minutes within a training session with an otherwise normally functioning device, then there should be suspicion that an actual arrhythmia has occurred.

My Recent Experience With SVT

Diagram 1:  The first indication that something
unusual had occurred was during the
post-activity review of 
heart rate data.
As "luck" would have it, this is exactly what happened to me during a recent fat bike ride. At nearly 50 years of age I have had the good health and fortune to have trained as an endurance athlete consistently for the past 30+ years. And working in the field of cardiology as a clinical exercise physiologist during much of that time, I have had a number of advanced diagnostic procedures performed including a 12-lead ECG, echocardiogram, and maximum graded exercise test. All had been interpreted as within normal limits. So although I understand the cardiovascular pathophysiology of long-term exposure to high volumes of endurance exercise, I was nonetheless taken off guard when I reviewed the heart rate response from a recent ride. Nearly halfway through a typical fat bike ride with better than average conditions following a fairly strenuous but not unusual climb (for me), I noticed my heart rate failed to drop on the easy downhill coast. You can see from the shaded area in Diagram 1 that not only did my heart rate fail to drop when I started back downhill, it actually accelerated above my average climbing heart rate (150 b/min vs. 180 b/min). Because my heart rate display was hidden under the sleeve of my jacket I was completely unaware during the activity that anything was out of the ordinary. The abnormally elevated heart rate spontaneously resolved after approximately 10 minutes. While there is absolutely no way to tell exactly what this abnormal heart rate was, the sudden onset, the rate, and spontaneous resolution are all highly suggestive of supraventricular tachycardia.

Diagram 2:  Two exact rides with one demonstrating
a suspiciously sudden elevated heart rate.
This frank episode had me wondering if it had happened before so I took a little closer look at some recent training data and low and behold I found another asymptomatic occurrence. This time on my hard tail single-speed bike and on pavement. And luckily I had another exact ride (route and equipment) for comparison. Diagram 2 is a comparative study of two exact rides on different days but on the same bike. The above heart rate data shows my "normal" heart rate response to this level of challenge. My heart rate increases during the climb and then decreases during the descent. This is very typical in cycling. However, the bottom heart rate data shows a failure of my heart rate to drop following the second ascent and subsequent descent. Although a little slower than my "episode" on the fat bike, this shaded area represents an average heart rate in the 160's and is consistent with SVT and because it occurred during a descent makes it suspicious.

Take Home Message
It's important to note that the diagnosis of SVT cannot be made by analyzing heart rate data solely although it is often the first indication the arrhythmia has occurred. You should become suspicious if when analyzing your heart rate data in the post-activity period you notice a sudden increase in heart rate (150-200 beats/min) that is inconsistent with the effort performed. If accompanied by the symptoms previously described and if it's a new phenomena to you, it's wise to contact your healthcare provider for follow-up. This follow-up will almost certainly include a physical exam and should include a 12-lead ECG. The paroxysmal nature of this arrhythmia makes it very difficult to document with electrocardiography. Many endurance athletes report having to wear an "event recorder" for multiple days including during exercise but without "uncovering" the arrhythmia. This often leads physicians to "speculate" what is actually happening. If however the arrhythmia is documented with an ECG and it has become performance-limiting, cardiologists may decide to either ablate (ie. destroy) the small cluster of cells in the atria causing the problem or slow the electrical conduction of the heart with a medication in the class known as beta blockers.

While this abnormal heart rhythm does not necessarily portend serious medical consequences in otherwise healthy hearts, it is worth noting and should always be followed up with a visit to your healthcare provider to rule out occult causes or other more serious tachyarrhythmias like ventricular tachycardia if you are symptomatic.

1 Mayo Clinic

Wednesday, March 7, 2018

Training Interference: Kicking It Down The Road

If you can't get in today's workout
should you kick it down the road?
"Why do today what you can put off until tomorrow?"  ~Anonymous

The variable of interference is an integral part of every endurance training plan.  In every day practice the concept helps to answer the question, "If I miss today's training unit should I push it to tomorrow?".  The answer is almost always "perhaps", but let's look at why.

In the programming of endurance sports training, interference implies that one training unit has the potential to impact another training unit.  The magnitude of this interaction almost always is directly related to the time proximity of the two training units.  That is to say, the closer the training units are stacked together with respect to time, the greater the potential for them to interact.  When training programs are designed, this relationship between training units is fairly precisely orchestrated.

For simplicity let's categorize interference three ways; maximal, potential, and minimal. An example of all three is depicted in the training log below.

Maximal Interference
When performed on the same day, two training units have great potential to interfere with each other.  The type, duration, and intensity of the training unit will determine the amount of time needed for recovery (complete or incomplete) and therefore the magnitude of interference exerted on the subsequent training unit.  In this example, a running-specific hill workout precedes a mobility/strength training unit.  Because this training cycle represents a specific preparation phase for an upcoming event (within 4-8 weeks), running is given priority over mobility and strength development.  When two training units are scheduled and performed on the same day it can be assumed that the first training unit will maximally interfere with the subsequent training unit.  Sometimes there is an attempt to avoid this interaction (as in the case of scheduling the running unit first), and sometimes the interaction is used purposefully (as in the case of pre-fatiguing the sport-specific soft-tissues with "doubles").

Potential Interference
A common program design philosophy includes microcycle variability.  This is seen as following "hard" days with "easy" days to give the body's adaptive mechanisms a chance to do their work.  When multiple hard efforts are scheduled in sequence, not only is there less time for important training adaptations to occur, but the risk of overreaching is considerably higher.  In the example above, Thursday's steady-state workout is scheduled forty-eight hours prior to Saturday's long run.  This design is described as "potential interference" in so much as there is likely to be some carried fatigue from Thursday without compromising Saturday's training unit.  This carried fatigue is both purposeful and potentially important with regard to sport-specific performance.  In other words, marathon and ultramarathon sports have both a strength endurance and metabolic endurance component.  Performing Saturday's long run on some carried fatigue helps to prepare the athlete for the physical and energetic demands later in races.

Minimal Interference
Lastly, there are times in which training units are scheduled to minimally interact with each other as in the case of these Saturday long runs.  Although often this more a function of time availability, it does end up serving an important design benefit.  Training units of two hours in duration or longer, place significant stress loads on the body.  This includes the structural components (ie. musculoskeletal system), bio energetic systems (ie. glycogen and fat), and immune system.  The ability to successfully complete these long training units is vital to sport-specific performance.  Therefore while some carried fatigue is beneficial (as in the potential interference example above), an excessive amount of carried fatigue not only potentially compromising the successful completion of the training unit, but is also significantly increases the risk of soft-tissue injuries and illness.

In summary, because most weekly training schedules often use all three forms of interference, be careful when you "kick a training unit down the road" by moving it to the next day.