PT on the Net Research

Using Vision Drills to Assess the Parasympathetic Nervous System

Learning Objectives

  1. Identify the stressors that may lead to sympathetic dominance.
  2. Understand the role between peripheral vision and the sympathetic and parasympathetic nervous systems.
  3. Learn the steps to assessing peripheral vision.
  4. Understand how to adjust a client’s training based on changes in their peripheral field.

Whether you are working with a client who exercises sporadically, has a regular exercise routine, or is a highly skilled athlete, the goal is to provide enough stress in their training program to elicit an adaptive response. However, the stress also puts the client in more of a “sympathetic state”, which may be associated to a person who pushes themselves too hard or worries too much (Wilson, 2016). When stress accumulates without sufficient recovery, injury and overtraining are often the result.  If trainers can identify factors that can contribute to sympathetic dominance and assess when stress levels are getting too high, they can modify the client’s training and keep them progressing without risking injury or overtraining.

What drives clients into sympathetic dominance?

Simply put, it is stress or anything the body perceives as a threat that is associated to sympathetic dominance.  It would be great if trainers only needed to consider the stress of the client’s workout.  However, stress from all areas of life affects the client’s ability to recover. All the stresses that your clients encounter add up over time and a tipping point is reached when stress levels are too high, recovery is insufficient, or a combination of both. These stressors include, but are not limited to:

The list could go on and on.  Even if your clients are not training rigorously every day, the rest of their lives could be throwing the sympathetic system into overdrive and compromising their ability to recover.

Doing daily assessments with your clients before and during their workouts can assist you in determining how intensely a client should train that day, if at all. It also will help you decide when additional recovery work is needed to reduce sympathetic dominance and support the client being more in a parasympathetic state.

Assessing Client Readiness

There are many tools that can be used to assess client readiness, such as heart rate and heart rate variability. However, having an assessment tool that requires no additional tools or apps and can be performed quickly and easily has value for both trainers and clients.  One such tool is the client’s vision.

Including vision training or assessments may seem to be outside of the scope of practice for trainers. However, consider how much vision plays a part in almost every movement we make. How can you ask a client to jump, cut across the field, or do any number of exercises without assessing their vision?  In assessing readiness to train, you are not looking at whether a client can read letters on a wall, like at an optometrist appointment. You want to specifically assess the client’s peripheral vision.

Stress and Peripheral Vision

Rogers and Landers (2005) found that both negative life event stress (N-LES) and potentially stressful athletic situations led to peripheral narrowing. Janelle, Singer, and Williams (1992) found that increased levels of anxiety in an auto-racing simulation altered the subject’s ability to acquire information from their peripheral vision.  While the situations may be different, the conclusions are the same.  Increased levels of stress and anxiety narrowed the subjects’ visual field and their ability to perceive information in their periphery. 

Compromised peripheral vision can lead to injury.  In sports, coaches can easily see how compromised peripheral vision sets an athlete up for injury. While the athlete needs to focus on the task in front of them, they simultaneously need to be able to perceive opportunities and threats in the periphery.

Narrowing of the peripheral vision, then, can be a good indication of when your client is acutely or chronically stressed.  It provides valuable information as to the readiness of your client to train and the degree to which their system is ready to handle additional stress.

How to Assess Peripheral Vision

First, you need to establish a baseline with your clients. This means that before beginning your next training cycle with them or after non-training days, do the assessment below on several consecutive days to determine your clients’ baseline peripheral vision.

Assessment Protocol:

  1. Have the client make “bunny ears” with their index and middle fingers and extend their arms out to the sides. (See Photo #1)
  2. Have the client stare at a dot or something directly in front of them and make sure that they are unable to see their fingers in their peripheral visual field.
  3. Have them wiggle their fingers as they horizontally adduct their shoulders, keeping the arms straight. (See Photo #2)
  4. When the client can see their fingers in their peripheral vision, have them stop moving their arms toward the midline.
  5. This is their baseline peripheral visual field.
  6. Note the approximate distance or degrees that a client moves their arms forward before seeing their fingers.

Photo Credit: Teri Maloney
Model Credit: Tony Maloney

When performing the assessment, keep these points in mind:

The left and right peripheral visual fields will not likely be even.

Make sure the client’s eyes are staring straight ahead, as they will want to shift their eyes side to side to find their fingers.

Using Peripheral Vision in Training

Before each training session, have the client do this assessment. If their peripheral field on either side has decreased, they are likely experiencing more stress than their system can handle, causing peripheral narrowing. Training that day will need to be modified to support the client’s need to recover and be more in the parasympathetic state. On the other hand, if their peripheral field is equal to or wider than their baseline, it indicates that the client’s stress levels are lower and their system may be able to handle more intensity or workload in their training.

Additionally, this assessment can be repeated in between sets.  If their peripheral field has not returned to the baseline measurement, their body has not yet fully recovered from the last exercise and they may need additional rest time before performing the next exercise.  If after additional rest their peripheral field is still narrowed, the client may benefit from stopping training for that day. Focus on breathing or other recovery methods that will put them in a parasympathetic state.

Of course, there may be times in which you will want the client to continue training even when they have not recovered to challenge their ability to handle additional stress. This must be done systematically and with caution. When this method is employed, ensure that the client does extra recovery work both before and after training to counteract the additional sympathetic stimulus.


Using the peripheral visual field to assess the client’s readiness to train will take some time and practice for both the client and the trainer, especially in assessing the more subtle changes.  However, using this method is a quick and easy way to assess whether or not the client’s system is able to handle additional stress during the training session or if more recovery is needed. By honing this method, you and your clients can keep making progress while staying clear of injury and overtraining!


Janelle, C. M., Singer, R. N., & Williams, A. M. (1992). External distraction and attentional narrowing: Visual search evidence. Journal of Sport and Exercise Psychology, 21(1), 70-91.

Rogers, T. J., & Landers, D. M. (2005). Mediating effects of peripheral vision in the life event stress/athletic injury relationship. Journal of Sport and Exercise Psychology, 27(3), 271-288.

Wilson, L.D. (2016). Sympathetic dominance. Retrieved from: