Intensity Variations - Strength, Cardiovascular & Brain functions...

When it is about having better body composition (more muscle mass and lesser fat %), a quantified nutrition backed by some resistance training does wonder, however the ever long debate upon the importance of cardiovascular exercises during the process is a food for thought! While you can’t simply eliminate its essence as a separate entity in training type, the bigger question that pops to us is the importance of intensity in a training program, be it resistance or even cardiovascular exercises and how can it be manipulated with time and phase, irrespective of our fitness goals.

The effects of intensity as a training variable on the physical aspect has been a topic of discussion for quite some time, however its impact on the neuron and brain function with a lesser attention given, has been found to coincide with one conclusion of how exercises in any form improves the overall brain functioning! So, the next question - “which one is effective enough and in what ways?” But, before we jump onto this question, it’s important to understand the term Intensity itself and break it down in all senses.

Well, it’s similar to the enthusiasm you might hold if I were to tell you a secret to getting abs in just 4 weeks. SShh, let's not reveal it here!

Technically, it is the quality or state of being intense or how extreme a degree of measuring some component could be. When we say exercise intensity, it is majorly the amount of physical power that the body uses while performing certain movements or activity. As an important variable in training science, the growth of our body and performance is pretty much a directive of intensity along with other parameters.

Intensity in strength training refers to the maximal load being lifted at that moment (during that set or rep for the exercise) and how heavy or light that weight is for the body. Say, you were training the exercise squats with a certain number of sets and reps with x amount of load (say 10 kgs overall), then that load simply means the intensity in that exercise session. Perhaps, intensity is the magnitude of resistance used and commonly evaluated as the % of a one repetition max for a lift. But, what are the various ways in which one can manipulate the Intensity in strength training?

Technically, you gotta add the load to increase the measurable “ Intensity” in your training, however, there are various ways in which you can make the lift or session more intense, such as:

• Increasing the range of motion (ROM) - how far the joint angle can move. Eg- going for a deep squat.

• Paused reps - Going with paused movements when the muscle tissues are loaded with weight.

• Training with Tempo - Keeping a practice of slower movements at eccentric phase (when the muscle length under tension increases or the lowering phase), while keeping an explosive drive during the concentric phase (when the muscle fibers come back to normal state).

• Reducing rest intervals can also help make a session more intense, although on a regular day it’s always a better idea to take enough rest between two sets or exercises, so that the breath comes to normal state which can help you lift to your max potential.

So, what about Intensity in cardio vascular exercises? The exercise intensity for cardiovascular training is measured through the heart rate, which is best termed as the Target Heart Rate, that helps us identify if we are making the most of health benefits upon the heart, yet staying at a safe level. It is basically a range of numbers that tells us how fast our hearts should be beating while exercising. The Target Heart Rate is calculated as a % of max safe heart rate (usually between 50-85 %), while the max rate varies with age (subtracted from 220). Eg - A 30 years old person will have max heart rate as 190 beats/ min, while the safe heart rate zone will be around 95 - 160 beats/ min.

The different types of cardio activities with respect to the heart rates are LISS - Low Intensity Steady State cardio, MISS - Moderate Intensity Steady State cardio, HIIT - High Intensity Interval Training. LISS is just under cardiovascular adaptations, with speed being similar to walking and energy expenditure being on the lower side too, while MISS is roughly at 60 % of VO2max and similar to regular endurance-based training. On the other hand, HIIT burns a similar amount of energy in a considerably shorter interval of time with a higher heart rate (usually as high as around 80-95 % of your max heart rate). So, to manipulate the intensity of any cardio vascular exercise, one can reduce the rest intervals or keep varying around the pace of his/ her training during that activity (maybe changing the speed every 1-2 mins).

Final one, what about the brain functioning?

Citing the study wherein 25 male athletes underwent individual assessments using an incremental treadmill test, with a low and high intensity exercise on alternate days for 30 mins each, further which the participants took a behavioral test on positive and negative mood that showed a significant increase in positive mood after both exercise intensities.

The verdict: The study conducted showed that the low intensity exercise led to increased functional connectivity in networks associated with cognitive processing and attention, which means it helps improving the process of thinking, knowing and remembering, judging, problem solving and analysis and planning.

Whereas, high intensity was seen to increase functional connectivity in networks related to effective, emotional processes, which perhaps can help one be more aware of his/ her expressions and feelings, thus being more responsive than being reactive. High intensity exercises also led to decreased functional connectivity in networks associated with motor function.

So, what's the takeaway?

Exercises in any form and intensity has a major role to play in improving our health parameters, be it physical or brain, while not doing should not be a wise idea, varying with intensity and other variables and aspects is a good way to identify your overall health and fitness quotient.

References:

https://www.eurekalert.org/pub_releases/2020-01/ip-hal013020.php

https://www.theweek.in/news/health/2020/02/03/Exercise-of-varying-intensities-may-influence-brain-function-differently-Study.html